Merge pull request 'vars: docs' (#4119) from vars-docs into main
Reviewed-on: https://git.clan.lol/clan/clan-core/pulls/4119
This commit is contained in:
Luis Hebendanz
@@ -63,6 +63,12 @@ nav:
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- ClanServices: guides/clanServices.md
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- Backup & Restore: guides/backups.md
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- Disk Encryption: guides/disk-encryption.md
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- Vars:
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- Overview: guides/vars-overview.md
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- Getting Started: guides/vars-backend.md
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- Concepts: guides/vars-concepts.md
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- Advanced Examples: guides/vars-advanced-examples.md
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- Troubleshooting: guides/vars-troubleshooting.md
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- Age Plugins: guides/age-plugins.md
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- Secrets management: guides/secrets.md
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- Networking: guides/networking.md
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@@ -1,148 +1,45 @@
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# Generators
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Defining a linux user's password via the nixos configuration previously required running `mkpasswd ...` and then copying the hash back into the nix configuration.
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Generators are the core mechanism of the clan vars system for automating the creation and management of generated files, especially secrets, in your NixOS configurations.
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In this example, we will guide you through automating that interaction using clan `vars`.
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## What are Generators?
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For a more general explanation of what clan vars are and how it works, see the intro of the [Reference Documentation for vars](../reference/clan.core/vars.md)
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Generators solve a common problem: instead of manually running commands like `mkpasswd` to create password hashes and copying them into your configuration, generators automate this process declaratively.
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This guide assumes
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- Clan is set up already (see [Getting Started](../guides/getting-started/index.md))
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- a machine has been added to the clan (see [Adding Machines](../guides/getting-started/add-machines.md))
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A generator defines:
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This section will walk you through the following steps:
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- **Input prompts**: Values to request from users (passwords, names, etc.)
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- **Generation script**: Logic to transform inputs into outputs
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- **Output files**: Generated files that can be secrets or public data
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- **Dependencies**: Other generators this one depends on
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- **Runtime inputs**: Tools and packages needed by the script
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1. declare a `generator` in the machine's nixos configuration
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2. inspect the status via the Clan CLI
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3. generate the vars
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4. observe the changes
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5. update the machine
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6. share the root password between machines
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7. change the password
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## Key Benefits
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## Declare a generator
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- **Reproducible**: Same inputs produce same outputs across machines
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- **Declarative**: Defined in your NixOS configuration alongside usage
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- **Secure**: Automatic handling of secrets storage and deployment
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- **Collaborative**: Shared generators work across team environments
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- **Automated**: No manual copy-paste of generated values
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In this example, a `vars` `generator` is used to:
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## Common Use Cases
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- prompt the user for the password
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- run the required `mkpasswd` command to generate the hash
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- store the hash in a file
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- expose the file path to the nixos configuration
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- **Password hashing**: Generate secure password hashes for user accounts
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- **SSH keys**: Create and manage SSH host and user keys
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- **Certificates**: Generate TLS certificates and certificate authorities
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- **API tokens**: Create secure random tokens for services
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- **Configuration files**: Generate config files that depend on secrets
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Create a new nix file `root-password.nix` with the following content and import it into your `configuration.nix`
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```nix
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{config, pkgs, ...}: {
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## Learning Path
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clan.core.vars.generators.root-password = {
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# prompt the user for a password
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# (`password-input` being an arbitrary name)
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prompts.password-input.description = "the root user's password";
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prompts.password-input.type = "hidden";
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# don't store the prompted password itself
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prompts.password-input.persist = false;
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# define an output file for storing the hash
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files.password-hash.secret = false;
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# define the logic for generating the hash
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script = ''
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cat $prompts/password-input | mkpasswd -m sha-512 > $out/password-hash
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'';
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# the tools required by the script
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runtimeInputs = [ pkgs.mkpasswd ];
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};
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1. **Start here**: [Vars Getting Started Guide](../guides/vars-backend.md) - Hands-on tutorial with practical examples
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2. **Understand the architecture**: [Vars Concepts Guide](../guides/vars-concepts.md) - Deep dive into design principles and patterns
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3. **Explore complex scenarios**: [Advanced Examples](../guides/vars-advanced-examples.md) - Real-world patterns and best practices
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4. **Troubleshoot issues**: [Troubleshooting Guide](../guides/vars-troubleshooting.md) - Common problems and solutions
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# ensure users are immutable (otherwise the following config might be ignored)
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users.mutableUsers = false;
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# set the root password to the file containing the hash
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users.users.root.hashedPasswordFile =
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# clan will make sure, this path exists
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config.clan.core.vars.generators.root-password.files.password-hash.path;
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}
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```
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## API Reference
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## Inspect the status
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For complete configuration options and technical details, see:
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Executing `clan vars list`, you should see the following:
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```shellSession
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$ clan vars list my_machine
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root-password/password-hash: <not set>
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```
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...indicating that the value `password-hash` for the generator `root-password` is not set yet.
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## Generate the values
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This step is not strictly necessary, as deploying the machine via `clan machines update` would trigger the generator as well.
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To run the generator, execute `clan vars generate` for your machine
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```shellSession
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$ clan vars generate my_machine
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Enter the value for root-password/password-input (hidden):
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```
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After entering the value, the updated status is reported:
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```shellSession
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Updated var root-password/password-hash
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old: <not set>
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new: $6$RMats/YMeypFtcYX$DUi...
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```
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## Observe the changes
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With the last step, a new file was created in your repository:
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`vars/per-machine/my-machine/root-password/password-hash/value`
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If the repository is a git repository, a commit was created automatically:
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```shellSession
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$ git log -n1
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commit ... (HEAD -> master)
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Author: ...
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Date: ...
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Update vars via generator root-password for machine grmpf-nix
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```
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## Update the machine
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```shell
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clan machines update my_machine
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```
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## Share root password between machines
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If we just imported the `root-password.nix` from above into more machines, clan would ask for a new password for each additional machine.
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If the root password instead should only be entered once and shared across all machines, the generator defined above needs to be declared as `shared`, by adding `share = true` to it:
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```nix
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{config, pkgs, ...}: {
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clan.vars.generators.root-password = {
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share = true;
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# ...
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}
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}
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```
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Importing that shared generator into each machine, will ensure that the password is only asked once the first machine gets updated and then re-used for all subsequent machines.
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## Change the root password
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Changing the password can be done via this command.
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Replace `my-machine` with your machine.
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If the password is shared, just pick any machine that has the generator declared.
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```shellSession
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$ clan vars generate my-machine --generator root-password --regenerate
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...
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Enter the value for root-password/password-input (hidden):
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Input received. Processing...
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...
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Updated var root-password/password-hash
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old: $6$tb27m6EOdff.X9TM$19N...
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new: $6$OyoQtDVzeemgh8EQ$zRK...
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```
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## Further Reading
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- [Reference Documentation for `clan.core.vars` NixOS options](../reference/clan.core/vars.md)
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- [Reference Documentation for the `clan vars` CLI command](../reference/cli/vars.md)
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- [Vars NixOS Module Reference](../reference/clan.core/vars.md) - All configuration options
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- [Vars CLI Reference](../reference/cli/vars.md) - Command-line interface
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289
docs/site/guides/vars-advanced-examples.md
Normal file
289
docs/site/guides/vars-advanced-examples.md
Normal file
@@ -0,0 +1,289 @@
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# Advanced Vars Examples
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This guide demonstrates complex, real-world patterns for the vars system. For basic usage, see the [Getting Started guide](vars-backend.md).
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## Certificate Authority with Intermediate Certificates
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This example shows how to create a complete certificate authority with root and intermediate certificates using dependencies.
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```nix
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{
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# Generate root CA (not deployed to machines)
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clan.core.vars.generators.root-ca = {
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files."ca.key" = {
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secret = true;
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deploy = false; # Keep root key offline
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};
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files."ca.crt".secret = false;
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runtimeInputs = [ pkgs.step-cli ];
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script = ''
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step certificate create "My Root CA" \
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$out/ca.crt $out/ca.key \
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--profile root-ca \
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--no-password \
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--not-after 87600h
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'';
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};
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# Generate intermediate key
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clan.core.vars.generators.intermediate-key = {
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files."intermediate.key" = {
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secret = true;
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deploy = true;
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};
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runtimeInputs = [ pkgs.step-cli ];
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script = ''
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step crypto keypair \
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$out/intermediate.pub \
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$out/intermediate.key \
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--no-password
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'';
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};
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# Generate intermediate certificate signed by root
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clan.core.vars.generators.intermediate-cert = {
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files."intermediate.crt".secret = false;
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dependencies = [
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"root-ca"
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"intermediate-key"
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];
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runtimeInputs = [ pkgs.step-cli ];
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script = ''
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step certificate create "My Intermediate CA" \
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$out/intermediate.crt \
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$in/intermediate-key/intermediate.key \
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--ca $in/root-ca/ca.crt \
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--ca-key $in/root-ca/ca.key \
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--profile intermediate-ca \
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--not-after 8760h \
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--no-password
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'';
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};
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# Use the certificates in services
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services.nginx.virtualHosts."example.com" = {
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sslCertificate = config.clan.core.vars.generators.intermediate-cert.files."intermediate.crt".value;
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sslCertificateKey = config.clan.core.vars.generators.intermediate-key.files."intermediate.key".path;
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};
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}
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```
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## Multi-Service Secret Sharing
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Generate secrets that multiple services can use:
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```nix
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{
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# Generate database credentials
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clan.core.vars.generators.database = {
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share = true; # Share across machines
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files."password" = { };
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files."connection-string" = { };
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prompts.dbname = {
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description = "Database name";
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type = "line";
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};
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script = ''
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# Generate password
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tr -dc 'A-Za-z0-9' < /dev/urandom | head -c 32 > $out/password
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# Create connection string
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echo "postgresql://app:$(cat $out/password)@localhost/$prompts/dbname" \
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> $out/connection-string
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'';
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};
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# PostgreSQL uses the password
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services.postgresql = {
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enable = true;
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initialScript = pkgs.writeText "init.sql" ''
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CREATE USER app WITH PASSWORD '${
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builtins.readFile config.clan.core.vars.generators.database.files."password".path
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}';
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'';
|
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};
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|
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# Application uses the connection string
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systemd.services.myapp = {
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serviceConfig.EnvironmentFile =
|
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config.clan.core.vars.generators.database.files."connection-string".path;
|
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};
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}
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```
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|
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## SSH Host Keys with Certificates
|
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|
||||
Generate SSH host keys and sign them with a CA:
|
||||
|
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```nix
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{
|
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# SSH Certificate Authority (shared)
|
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clan.core.vars.generators.ssh-ca = {
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share = true;
|
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files."ca" = { secret = true; deploy = false; };
|
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files."ca.pub" = { secret = false; };
|
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runtimeInputs = [ pkgs.openssh ];
|
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script = ''
|
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ssh-keygen -t ed25519 -N "" -f $out/ca
|
||||
mv $out/ca.pub $out/ca.pub
|
||||
'';
|
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};
|
||||
|
||||
# Host-specific SSH keys
|
||||
clan.core.vars.generators.ssh-host = {
|
||||
files."ssh_host_ed25519_key" = {
|
||||
secret = true;
|
||||
owner = "root";
|
||||
group = "root";
|
||||
mode = "0600";
|
||||
};
|
||||
files."ssh_host_ed25519_key.pub" = { secret = false; };
|
||||
files."ssh_host_ed25519_key-cert.pub" = { secret = false; };
|
||||
dependencies = [ "ssh-ca" ];
|
||||
runtimeInputs = [ pkgs.openssh ];
|
||||
script = ''
|
||||
# Generate host key
|
||||
ssh-keygen -t ed25519 -N "" -f $out/ssh_host_ed25519_key
|
||||
|
||||
# Sign with CA
|
||||
ssh-keygen -s $in/ssh-ca/ca \
|
||||
-I "host:${config.networking.hostName}" \
|
||||
-h \
|
||||
-V -5m:+365d \
|
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$out/ssh_host_ed25519_key.pub
|
||||
'';
|
||||
};
|
||||
|
||||
# Configure SSH to use the generated keys
|
||||
services.openssh = {
|
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hostKeys = [{
|
||||
path = config.clan.core.vars.generators.ssh-host.files."ssh_host_ed25519_key".path;
|
||||
type = "ed25519";
|
||||
}];
|
||||
};
|
||||
}
|
||||
```
|
||||
|
||||
## WireGuard Mesh Network
|
||||
|
||||
Create a WireGuard configuration with pre-shared keys:
|
||||
|
||||
```nix
|
||||
{
|
||||
# Generate WireGuard keys for this host
|
||||
clan.core.vars.generators.wireguard = {
|
||||
files."privatekey" = {
|
||||
secret = true;
|
||||
owner = "systemd-network";
|
||||
mode = "0400";
|
||||
};
|
||||
files."publickey" = { secret = false; };
|
||||
files."preshared" = { secret = true; };
|
||||
runtimeInputs = [ pkgs.wireguard-tools ];
|
||||
script = ''
|
||||
# Generate key pair
|
||||
wg genkey > $out/privatekey
|
||||
wg pubkey < $out/privatekey > $out/publickey
|
||||
|
||||
# Generate pre-shared key
|
||||
wg genpsk > $out/preshared
|
||||
'';
|
||||
};
|
||||
|
||||
# Configure WireGuard
|
||||
networking.wireguard.interfaces.wg0 = {
|
||||
privateKeyFile = config.clan.core.vars.generators.wireguard.files."privatekey".path;
|
||||
|
||||
peers = [{
|
||||
publicKey = "peer-public-key-here";
|
||||
presharedKeyFile = config.clan.core.vars.generators.wireguard.files."preshared".path;
|
||||
allowedIPs = [ "10.0.0.2/32" ];
|
||||
}];
|
||||
};
|
||||
}
|
||||
```
|
||||
|
||||
## Conditional Generation Based on Machine Role
|
||||
|
||||
Generate different secrets based on machine configuration:
|
||||
|
||||
```nix
|
||||
{
|
||||
clan.core.vars.generators = lib.mkMerge [
|
||||
# All machines get basic auth
|
||||
{
|
||||
basic-auth = {
|
||||
files."htpasswd" = { };
|
||||
prompts.username = {
|
||||
description = "Username for basic auth";
|
||||
type = "line";
|
||||
};
|
||||
prompts.password = {
|
||||
description = "Password for basic auth";
|
||||
type = "hidden";
|
||||
};
|
||||
runtimeInputs = [ pkgs.apacheHttpd ];
|
||||
script = ''
|
||||
htpasswd -nbB "$prompts/username" "$prompts/password" > $out/htpasswd
|
||||
'';
|
||||
};
|
||||
}
|
||||
|
||||
# Only servers get API tokens
|
||||
(lib.mkIf config.services.myapi.enable {
|
||||
api-tokens = {
|
||||
files."admin-token" = { };
|
||||
files."readonly-token" = { };
|
||||
runtimeInputs = [ pkgs.openssl ];
|
||||
script = ''
|
||||
openssl rand -hex 32 > $out/admin-token
|
||||
openssl rand -hex 16 > $out/readonly-token
|
||||
'';
|
||||
};
|
||||
})
|
||||
];
|
||||
}
|
||||
```
|
||||
|
||||
## Backup Encryption Keys
|
||||
|
||||
Generate and manage backup encryption keys:
|
||||
|
||||
```nix
|
||||
{
|
||||
clan.core.vars.generators.backup = {
|
||||
share = true; # Same key for all backup sources
|
||||
files."encryption.key" = {
|
||||
secret = true;
|
||||
deploy = true;
|
||||
};
|
||||
files."encryption.pub" = { secret = false; };
|
||||
runtimeInputs = [ pkgs.age ];
|
||||
script = ''
|
||||
# Generate age key pair
|
||||
age-keygen -o $out/encryption.key 2>/dev/null
|
||||
|
||||
# Extract public key
|
||||
grep "public key:" $out/encryption.key | cut -d: -f2 | tr -d ' ' \
|
||||
> $out/encryption.pub
|
||||
'';
|
||||
};
|
||||
|
||||
# Use in backup service
|
||||
services.borgbackup.jobs.system = {
|
||||
encryption = {
|
||||
mode = "repokey-blake2";
|
||||
passCommand = "cat ${config.clan.core.vars.generators.backup.files."encryption.key".path}";
|
||||
};
|
||||
};
|
||||
}
|
||||
```
|
||||
|
||||
## Tips and Best Practices
|
||||
|
||||
1. **Use dependencies** to build complex multi-stage generations
|
||||
2. **Share generators** when the same secret is needed across machines
|
||||
3. **Set appropriate permissions** for service-specific secrets
|
||||
4. **Use prompts** for user-specific values that shouldn't be generated
|
||||
5. **Combine secret and non-secret files** in the same generator when they're related
|
||||
6. **Use conditional generation** with `lib.mkIf` for role-specific secrets
|
||||
155
docs/site/guides/vars-backend.md
Normal file
155
docs/site/guides/vars-backend.md
Normal file
@@ -0,0 +1,155 @@
|
||||
|
||||
!!! Note
|
||||
This guide demonstrates the vars system for managing secrets and generated files
|
||||
|
||||
|
||||
Defining a linux user's password via the nixos configuration previously required running `mkpasswd ...` and then copying the hash back into the nix configuration.
|
||||
|
||||
In this example, we will guide you through automating that interaction using clan `vars`.
|
||||
|
||||
For architectural concepts and design principles, see the [Concepts guide](vars-concepts.md). For the complete API reference, see the [vars module documentation](../reference/clan.core/vars.md).
|
||||
|
||||
This guide assumes
|
||||
- Clan is set up already (see [Getting Started](../guides/getting-started/index.md))
|
||||
- a machine has been added to the clan (see [Adding Machines](getting-started/add-machines.md))
|
||||
|
||||
This section will walk you through the following steps:
|
||||
|
||||
1. declare a `generator` in the machine's nixos configuration
|
||||
2. inspect the status via the Clan CLI
|
||||
3. generate the vars
|
||||
4. observe the changes
|
||||
5. update the machine
|
||||
6. share the root password between machines
|
||||
7. change the password
|
||||
|
||||
## Declare the generator
|
||||
|
||||
In this example, a `vars` `generator` is used to:
|
||||
|
||||
- prompt the user for the password
|
||||
- run the required `mkpasswd` command to generate the hash
|
||||
- store the hash in a file
|
||||
- expose the file path to the nixos configuration
|
||||
|
||||
Create a new nix file `root-password.nix` with the following content and import it into your `configuration.nix`
|
||||
```nix
|
||||
{config, pkgs, ...}: {
|
||||
|
||||
clan.core.vars.generators.root-password = {
|
||||
# prompt the user for a password
|
||||
# (`password-input` being an arbitrary name)
|
||||
prompts.password-input.description = "the root user's password";
|
||||
prompts.password-input.type = "hidden";
|
||||
# don't store the prompted password itself
|
||||
prompts.password-input.persist = false;
|
||||
# define an output file for storing the hash
|
||||
files.password-hash.secret = false;
|
||||
# define the logic for generating the hash
|
||||
script = ''
|
||||
cat $prompts/password-input | mkpasswd -m sha-512 > $out/password-hash
|
||||
'';
|
||||
# the tools required by the script
|
||||
runtimeInputs = [ pkgs.mkpasswd ];
|
||||
};
|
||||
|
||||
# ensure users are immutable (otherwise the following config might be ignored)
|
||||
users.mutableUsers = false;
|
||||
# set the root password to the file containing the hash
|
||||
users.users.root.hashedPasswordFile =
|
||||
# clan will make sure, this path exists
|
||||
config.clan.core.vars.generators.root-password.files.password-hash.path;
|
||||
}
|
||||
```
|
||||
|
||||
## Inspect the status
|
||||
|
||||
Executing `clan vars list`, you should see the following:
|
||||
```shellSession
|
||||
$ clan vars list my_machine
|
||||
root-password/password-hash: <not set>
|
||||
```
|
||||
|
||||
...indicating that the value `password-hash` for the generator `root-password` is not set yet.
|
||||
|
||||
## Generate the values
|
||||
|
||||
This step is not strictly necessary, as deploying the machine via `clan machines update` would trigger the generator as well.
|
||||
|
||||
To run the generator, execute `clan vars generate` for your machine
|
||||
```shellSession
|
||||
$ clan vars generate my_machine
|
||||
Enter the value for root-password/password-input (hidden):
|
||||
```
|
||||
|
||||
After entering the value, the updated status is reported:
|
||||
```shellSession
|
||||
Updated var root-password/password-hash
|
||||
old: <not set>
|
||||
new: $6$RMats/YMeypFtcYX$DUi...
|
||||
```
|
||||
|
||||
## Observe the changes
|
||||
|
||||
With the last step, a new file was created in your repository:
|
||||
`vars/per-machine/my-machine/root-password/password-hash/value`
|
||||
|
||||
If the repository is a git repository, a commit was created automatically:
|
||||
```shellSession
|
||||
$ git log -n1
|
||||
commit ... (HEAD -> master)
|
||||
Author: ...
|
||||
Date: ...
|
||||
|
||||
Update vars via generator root-password for machine grmpf-nix
|
||||
```
|
||||
|
||||
## Update the machine
|
||||
|
||||
```shell
|
||||
clan machines update my_machine
|
||||
```
|
||||
|
||||
## Share root password between machines
|
||||
|
||||
If we just imported the `root-password.nix` from above into more machines, clan would ask for a new password for each additional machine.
|
||||
|
||||
If the root password instead should only be entered once and shared across all machines, the generator defined above needs to be declared as `shared`, by adding `share = true` to it:
|
||||
```nix
|
||||
{config, pkgs, ...}: {
|
||||
clan.core.vars.generators.root-password = {
|
||||
share = true;
|
||||
# ...
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Importing that shared generator into each machine, will ensure that the password is only asked once the first machine gets updated and then re-used for all subsequent machines.
|
||||
|
||||
## Change the root password
|
||||
|
||||
Changing the password can be done via this command.
|
||||
Replace `my-machine` with your machine.
|
||||
If the password is shared, just pick any machine that has the generator declared.
|
||||
|
||||
```shellSession
|
||||
$ clan vars generate my-machine --generator root-password --regenerate
|
||||
...
|
||||
Enter the value for root-password/password-input (hidden):
|
||||
Input received. Processing...
|
||||
...
|
||||
Updated var root-password/password-hash
|
||||
old: $6$tb27m6EOdff.X9TM$19N...
|
||||
|
||||
new: $6$OyoQtDVzeemgh8EQ$zRK...
|
||||
```
|
||||
|
||||
|
||||
## Further Reading
|
||||
|
||||
- [Understanding Vars Concepts](vars-concepts.md) - Learn about the architecture and core concepts
|
||||
- [Advanced Examples](vars-advanced-examples.md) - Complex real-world examples including certificates, SSH keys, and more
|
||||
- [Troubleshooting Guide](vars-troubleshooting.md) - Common issues and solutions
|
||||
- [Migration Guide](migrations/migration-facts-vars.md) - Migrate from legacy facts system
|
||||
- [Reference Documentation for `clan.core.vars` NixOS options](../reference/clan.core/vars.md)
|
||||
- [Reference Documentation for the `clan vars` CLI command](../reference/cli/vars.md)
|
||||
129
docs/site/guides/vars-concepts.md
Normal file
129
docs/site/guides/vars-concepts.md
Normal file
@@ -0,0 +1,129 @@
|
||||
# Understanding Clan Vars - Concepts & Architecture
|
||||
|
||||
This guide explains the architecture and design principles behind the vars system. For a hands-on tutorial, see the [Getting Started guide](vars-backend.md).
|
||||
|
||||
## Architecture Overview
|
||||
|
||||
The vars system provides a declarative, reproducible way to manage generated files (especially secrets) in NixOS configurations.
|
||||
|
||||
## Data Flow
|
||||
|
||||
```mermaid
|
||||
graph LR
|
||||
A[Generator Script] --> B[Output Files]
|
||||
C[User Prompts] --> A
|
||||
D[Dependencies] --> A
|
||||
B --> E[Secret Storage<br/>sops/password-store]
|
||||
B --> F[Nix Store<br/>public files]
|
||||
E --> G[Machine Deployment]
|
||||
F --> G
|
||||
```
|
||||
|
||||
## Key Design Principles
|
||||
|
||||
### 1. Declarative Generation
|
||||
|
||||
Unlike imperative secret management, vars are declared in your NixOS configuration and generated deterministically. This ensures reproducibility across deployments.
|
||||
|
||||
### 2. Separation of Concerns
|
||||
|
||||
- **Generation logic**: Defined in generator scripts
|
||||
- **Storage**: Handled by pluggable backends (sops, password-store, etc.)
|
||||
- **Deployment**: Managed by NixOS activation scripts
|
||||
- **Access control**: Enforced through file permissions and ownership
|
||||
|
||||
### 3. Composability Through Dependencies
|
||||
|
||||
Generators can depend on outputs from other generators, enabling complex workflows:
|
||||
|
||||
```nix
|
||||
# Dependencies create a directed acyclic graph (DAG)
|
||||
A → B → C
|
||||
↓
|
||||
D
|
||||
```
|
||||
|
||||
This allows building sophisticated systems like certificate authorities where intermediate certificates depend on root certificates.
|
||||
|
||||
### 4. Type Safety
|
||||
|
||||
The vars system distinguishes between:
|
||||
- **Secret files**: Only accessible via `.path`, deployed to `/run/secrets/`
|
||||
- **Public files**: Accessible via `.value`, stored in nix store
|
||||
|
||||
This prevents accidental exposure of secrets in the nix store.
|
||||
|
||||
## Storage Backend Architecture
|
||||
|
||||
The vars system uses pluggable storage backends:
|
||||
|
||||
- **sops** (default): Integrates with clan's existing sops encryption
|
||||
- **password-store**: For users already using pass
|
||||
|
||||
Each backend handles encryption/decryption transparently, allowing the same generator definitions to work across different security models.
|
||||
|
||||
## Timing and Lifecycle
|
||||
|
||||
### Generation Phases
|
||||
|
||||
1. **Pre-deployment**: `clan vars generate` creates vars before deployment
|
||||
2. **During deployment**: Missing vars are generated automatically
|
||||
3. **Regeneration**: Explicit regeneration with `--regenerate` flag
|
||||
|
||||
### The `neededFor` Option
|
||||
|
||||
Control when vars are available during system activation:
|
||||
|
||||
```nix
|
||||
files."early-secret" = {
|
||||
secret = true;
|
||||
neededFor = [ "users" "groups" ]; # Available early in activation
|
||||
};
|
||||
```
|
||||
|
||||
## Advanced Patterns
|
||||
|
||||
### Multi-Machine Coordination
|
||||
|
||||
The `share` option enables cross-machine secret sharing:
|
||||
|
||||
```mermaid
|
||||
graph LR
|
||||
A[Shared Generator] --> B[Machine 1]
|
||||
A --> C[Machine 2]
|
||||
A --> D[Machine 3]
|
||||
```
|
||||
|
||||
This is useful for:
|
||||
- Shared certificate authorities
|
||||
- Mesh VPN pre-shared keys
|
||||
- Cluster join tokens
|
||||
|
||||
### Generator Composition
|
||||
|
||||
Complex systems can be built by composing simple generators:
|
||||
|
||||
```
|
||||
root-ca → intermediate-ca → service-cert
|
||||
↓
|
||||
ocsp-responder
|
||||
```
|
||||
|
||||
Each generator focuses on one task, making the system modular and testable.
|
||||
|
||||
## Key Advantages
|
||||
|
||||
Compared to manual secret management, vars provides:
|
||||
|
||||
- **Declarative configuration**: Define once, generate consistently
|
||||
- **Dependency management**: Build complex systems with generator dependencies
|
||||
- **Type safety**: Separate handling of secret and public files
|
||||
- **User prompts**: Gather input when needed
|
||||
- **Easy regeneration**: Update secrets with a single command
|
||||
|
||||
## Next Steps
|
||||
|
||||
- [Practical Tutorial](vars-backend.md) - Step-by-step guide
|
||||
- [Advanced Examples](vars-advanced-examples.md) - Real-world patterns
|
||||
- [Troubleshooting](vars-troubleshooting.md) - Common issues
|
||||
- [Reference](../reference/clan.core/vars.md) - Complete API
|
||||
169
docs/site/guides/vars-overview.md
Normal file
169
docs/site/guides/vars-overview.md
Normal file
@@ -0,0 +1,169 @@
|
||||
# Vars System Overview
|
||||
|
||||
The vars system is clan's declarative solution for managing generated files, secrets, and dynamic configuration in your NixOS deployments. It eliminates the manual steps of generating credentials, certificates, and other dynamic values by automating these processes within your infrastructure-as-code workflow.
|
||||
|
||||
## What Problems Does Vars Solve?
|
||||
|
||||
### Before Vars: Manual Secret Management
|
||||
|
||||
Traditional NixOS deployments require manual steps for secrets and generated files:
|
||||
|
||||
```bash
|
||||
# Generate password hash manually
|
||||
mkpasswd -m sha-512 > /tmp/root-password-hash
|
||||
# Copy hash into configuration
|
||||
users.users.root.hashedPasswordFile = "/tmp/root-password-hash";
|
||||
```
|
||||
|
||||
This approach has several problems:
|
||||
- **Not reproducible**: Manual steps vary between team members
|
||||
- **Hard to maintain**: Updating secrets requires remembering manual commands
|
||||
- **Deployment friction**: Secrets must be managed outside of your configuration
|
||||
- **Team collaboration issues**: Sharing credentials securely is complex
|
||||
|
||||
### After Vars: Declarative Generation
|
||||
|
||||
With vars, the same process becomes declarative and automated:
|
||||
|
||||
```nix
|
||||
clan.core.vars.generators.root-password = {
|
||||
prompts.password.description = "Root password";
|
||||
prompts.password.type = "hidden";
|
||||
files.hash.secret = false;
|
||||
script = "mkpasswd -m sha-512 < $prompts/password > $out/hash";
|
||||
runtimeInputs = [ pkgs.mkpasswd ];
|
||||
};
|
||||
|
||||
users.users.root.hashedPasswordFile =
|
||||
config.clan.core.vars.generators.root-password.files.hash.path;
|
||||
```
|
||||
|
||||
## Core Benefits
|
||||
|
||||
- **🔄 Reproducible**: Same inputs always produce the same outputs
|
||||
- **📝 Declarative**: Defined alongside your NixOS configuration
|
||||
- **🔐 Secure**: Automatic secret storage and encrypted deployment
|
||||
- **👥 Collaborative**: Built-in sharing for team environments
|
||||
- **🚀 Automated**: No manual intervention required for deployments
|
||||
- **🔗 Integrated**: Works seamlessly with clan's deployment workflow
|
||||
|
||||
## How It Works
|
||||
|
||||
```mermaid
|
||||
graph TB
|
||||
A[Generator Declaration] --> B[clan vars generate]
|
||||
B --> C{Prompts User}
|
||||
C --> D[Execute Script]
|
||||
D --> E[Output Files]
|
||||
E --> F{Secret?}
|
||||
F -->|Yes| G[Encrypted Storage]
|
||||
F -->|No| H[Git Repository]
|
||||
G --> I[Deploy to Machine]
|
||||
H --> I
|
||||
I --> J[Available in NixOS]
|
||||
```
|
||||
|
||||
1. **Declare generators** in your NixOS configuration
|
||||
2. **Generate values** using `clan vars generate` (or automatically during deployment)
|
||||
3. **Store securely** in encrypted backends or version control
|
||||
4. **Deploy seamlessly** to your machines where they're accessible as file paths
|
||||
|
||||
## Common Use Cases
|
||||
|
||||
| Use Case | What Gets Generated | Benefits |
|
||||
|----------|-------------------|----------|
|
||||
| **User passwords** | Password hashes | No plaintext in config |
|
||||
| **SSH keys** | Host/user keypairs | Automated key rotation |
|
||||
| **TLS certificates** | Certificates + private keys | Automated PKI |
|
||||
| **Database credentials** | Passwords + connection strings | Secure service communication |
|
||||
| **API tokens** | Random tokens | Service authentication |
|
||||
| **Configuration files** | Complex configs with secrets | Dynamic config generation |
|
||||
|
||||
## Architecture Overview
|
||||
|
||||
The vars system has three main components:
|
||||
|
||||
### 1. **Generators**
|
||||
Define how to create files from inputs:
|
||||
- **Prompts**: Values requested from users
|
||||
- **Scripts**: Generation logic
|
||||
- **Dependencies**: Other generators this depends on
|
||||
- **Outputs**: Files that get created
|
||||
|
||||
### 2. **Storage Backends**
|
||||
Handle secret storage and deployment:
|
||||
- **sops**: Encrypted files in git (recommended)
|
||||
- **password-store**: GPG/age-based secret storage
|
||||
- **vm**: For development/testing
|
||||
|
||||
### 3. **Integration**
|
||||
Seamless NixOS integration:
|
||||
- File paths available at build time
|
||||
- Automatic deployment to machines
|
||||
- Service restarts on changes
|
||||
|
||||
## Learning Path
|
||||
|
||||
Ready to get started? Follow this recommended path:
|
||||
|
||||
### 1. **🚀 Hands-On Tutorial**
|
||||
[Vars Getting Started Guide](vars-backend.md)
|
||||
Start here for a practical walkthrough with password generation.
|
||||
|
||||
### 2. **🏗️ Understand the Design**
|
||||
[Vars Concepts & Architecture](vars-concepts.md)
|
||||
Deep dive into design principles and advanced patterns.
|
||||
|
||||
### 3. **💡 Real-World Examples**
|
||||
[Advanced Examples](vars-advanced-examples.md)
|
||||
Complex scenarios including certificates, SSH keys, and databases.
|
||||
|
||||
### 4. **🔧 Troubleshooting**
|
||||
[Troubleshooting Guide](vars-troubleshooting.md)
|
||||
Solutions for common issues and debugging techniques.
|
||||
|
||||
### 5. **📚 Complete Reference**
|
||||
- [NixOS Module Options](../reference/clan.core/vars.md)
|
||||
- [CLI Commands](../reference/cli/vars.md)
|
||||
|
||||
## Quick Start Example
|
||||
|
||||
Here's a complete example showing password generation and usage:
|
||||
|
||||
```nix
|
||||
# generator.nix
|
||||
{ config, pkgs, ... }: {
|
||||
clan.core.vars.generators.user-password = {
|
||||
prompts.password = {
|
||||
description = "User password";
|
||||
type = "hidden";
|
||||
};
|
||||
files.hash = { secret = false; };
|
||||
script = ''
|
||||
mkpasswd -m sha-512 < $prompts/password > $out/hash
|
||||
'';
|
||||
runtimeInputs = [ pkgs.mkpasswd ];
|
||||
};
|
||||
|
||||
users.users.myuser = {
|
||||
hashedPasswordFile =
|
||||
config.clan.core.vars.generators.user-password.files.hash.path;
|
||||
};
|
||||
}
|
||||
```
|
||||
|
||||
```bash
|
||||
# Generate the password
|
||||
clan vars generate my-machine
|
||||
|
||||
# Deploy to machine
|
||||
clan machines update my-machine
|
||||
```
|
||||
|
||||
## Migration from Facts
|
||||
|
||||
If you're currently using the legacy facts system, see our [Migration Guide](migrations/migration-facts-vars.md) for step-by-step instructions on upgrading to vars.
|
||||
|
||||
---
|
||||
|
||||
**Ready to start?** Head to the [Getting Started Guide](vars-backend.md) for your first hands-on experience with the vars system.
|
||||
266
docs/site/guides/vars-troubleshooting.md
Normal file
266
docs/site/guides/vars-troubleshooting.md
Normal file
@@ -0,0 +1,266 @@
|
||||
# Troubleshooting Vars
|
||||
|
||||
Quick reference for diagnosing and fixing vars issues. For basic usage, see the [Getting Started guide](vars-backend.md).
|
||||
|
||||
## Common Issues
|
||||
|
||||
### Generator Script Fails
|
||||
|
||||
**Symptom**: Error during `clan vars generate` or deployment
|
||||
|
||||
**Possible causes and solutions**:
|
||||
|
||||
1. **Missing runtime inputs**
|
||||
```nix
|
||||
# Wrong - missing required tool
|
||||
runtimeInputs = [ ];
|
||||
script = ''
|
||||
openssl rand -hex 32 > $out/secret # openssl not found!
|
||||
'';
|
||||
|
||||
# Correct
|
||||
runtimeInputs = [ pkgs.openssl ];
|
||||
```
|
||||
|
||||
2. **Wrong output path**
|
||||
```nix
|
||||
# Wrong - must use $out
|
||||
script = ''
|
||||
echo "secret" > ./myfile
|
||||
'';
|
||||
|
||||
# Correct
|
||||
script = ''
|
||||
echo "secret" > $out/myfile
|
||||
'';
|
||||
```
|
||||
|
||||
3. **Missing declared files**
|
||||
```nix
|
||||
files."config" = { };
|
||||
files."key" = { };
|
||||
script = ''
|
||||
# Wrong - only generates one file
|
||||
echo "data" > $out/config
|
||||
'';
|
||||
|
||||
# Correct - must generate all declared files
|
||||
script = ''
|
||||
echo "data" > $out/config
|
||||
echo "key" > $out/key
|
||||
'';
|
||||
```
|
||||
|
||||
### Cannot Access Generated Files
|
||||
|
||||
**Symptom**: "attribute 'value' missing" or file not found
|
||||
|
||||
**Solutions**:
|
||||
|
||||
1. **Secret files don't have `.value`**
|
||||
```nix
|
||||
# Wrong - secret files can't use .value
|
||||
files."secret" = { secret = true; };
|
||||
# ...
|
||||
environment.etc."app.conf".text =
|
||||
config.clan.core.vars.generators.app.files."secret".value;
|
||||
|
||||
# Correct - use .path for secrets
|
||||
environment.etc."app.conf".source =
|
||||
config.clan.core.vars.generators.app.files."secret".path;
|
||||
```
|
||||
|
||||
2. **Public files should use `.value`**
|
||||
```nix
|
||||
# Better for non-secrets
|
||||
files."cert.pem" = { secret = false; };
|
||||
# ...
|
||||
sslCertificate =
|
||||
config.clan.core.vars.generators.ca.files."cert.pem".value;
|
||||
```
|
||||
|
||||
### Dependencies Not Available
|
||||
|
||||
**Symptom**: "No such file or directory" when accessing `$in/...`
|
||||
|
||||
**Solution**: Declare dependencies correctly
|
||||
```nix
|
||||
clan.core.vars.generators.child = {
|
||||
# Wrong - missing dependency
|
||||
script = ''
|
||||
cat $in/parent/file > $out/newfile
|
||||
'';
|
||||
|
||||
# Correct
|
||||
dependencies = [ "parent" ];
|
||||
script = ''
|
||||
cat $in/parent/file > $out/newfile
|
||||
'';
|
||||
};
|
||||
```
|
||||
|
||||
### Permission Denied
|
||||
|
||||
**Symptom**: Service cannot read generated secret file
|
||||
|
||||
**Solution**: Set correct ownership and permissions
|
||||
```nix
|
||||
files."service.key" = {
|
||||
secret = true;
|
||||
owner = "myservice"; # Match service user
|
||||
group = "myservice";
|
||||
mode = "0400"; # Read-only for owner
|
||||
};
|
||||
```
|
||||
|
||||
### Vars Not Regenerating
|
||||
|
||||
**Symptom**: Changes to generator script don't trigger regeneration
|
||||
|
||||
**Solution**: Use `--regenerate` flag
|
||||
```bash
|
||||
clan vars generate my-machine --generator my-generator --regenerate
|
||||
```
|
||||
|
||||
### Prompts Not Working
|
||||
|
||||
**Symptom**: Script fails with "No such file or directory" for prompts
|
||||
|
||||
**Solution**: Access prompts correctly
|
||||
```nix
|
||||
# Wrong
|
||||
script = ''
|
||||
echo $password > $out/file
|
||||
'';
|
||||
|
||||
# Correct
|
||||
prompts.password.type = "hidden";
|
||||
script = ''
|
||||
cat $prompts/password > $out/file
|
||||
'';
|
||||
```
|
||||
|
||||
## Debugging Techniques
|
||||
|
||||
### 1. Check Generator Status
|
||||
|
||||
See what vars are set:
|
||||
```bash
|
||||
clan vars list my-machine
|
||||
```
|
||||
|
||||
### 2. Inspect Generated Files
|
||||
|
||||
For shared vars:
|
||||
```bash
|
||||
ls -la vars/shared/my-generator/
|
||||
```
|
||||
|
||||
For per-machine vars:
|
||||
```bash
|
||||
ls -la vars/per-machine/my-machine/my-generator/
|
||||
```
|
||||
|
||||
### 3. Test Generators Locally
|
||||
|
||||
Create a test script to debug:
|
||||
```nix
|
||||
# test-generator.nix
|
||||
{ pkgs ? import <nixpkgs> {} }:
|
||||
pkgs.stdenv.mkDerivation {
|
||||
name = "test-generator";
|
||||
buildInputs = [ pkgs.openssl ]; # Your runtime inputs
|
||||
buildCommand = ''
|
||||
# Your generator script here
|
||||
mkdir -p $out
|
||||
openssl rand -hex 32 > $out/secret
|
||||
ls -la $out/
|
||||
'';
|
||||
}
|
||||
```
|
||||
|
||||
Run with:
|
||||
```bash
|
||||
nix-build test-generator.nix
|
||||
```
|
||||
|
||||
### 4. Enable Debug Logging
|
||||
|
||||
Set debug mode:
|
||||
```bash
|
||||
clan --debug vars generate my-machine
|
||||
```
|
||||
|
||||
### 5. Check File Permissions
|
||||
|
||||
Verify generated secret permissions:
|
||||
```bash
|
||||
# On the target machine
|
||||
ls -la /run/secrets/
|
||||
```
|
||||
|
||||
## Recovery Procedures
|
||||
|
||||
### Regenerate All Vars
|
||||
|
||||
If vars are corrupted or need refresh:
|
||||
```bash
|
||||
# Regenerate all for a machine
|
||||
clan vars generate my-machine --regenerate
|
||||
|
||||
# Regenerate specific generator
|
||||
clan vars generate my-machine --generator my-generator --regenerate
|
||||
```
|
||||
|
||||
### Manual Secret Injection
|
||||
|
||||
For recovery or testing:
|
||||
```bash
|
||||
# Set a var manually (bypass generator)
|
||||
echo "temporary-secret" | clan vars set my-machine my-generator/my-file
|
||||
```
|
||||
|
||||
### Restore from Backup
|
||||
|
||||
Vars are stored in the repository:
|
||||
```bash
|
||||
# Restore previous version
|
||||
git checkout HEAD~1 -- vars/
|
||||
|
||||
# Check and regenerate if needed
|
||||
clan vars list my-machine
|
||||
```
|
||||
|
||||
## Storage Backend Issues
|
||||
|
||||
### SOPS Decryption Fails
|
||||
|
||||
**Symptom**: "Failed to decrypt" or permission errors
|
||||
|
||||
**Solution**: Ensure your user/machine has the correct age keys configured. Clan manages encryption keys automatically based on the configured users and machines in your flake.
|
||||
|
||||
Check that:
|
||||
1. Your machine is properly configured in the flake
|
||||
2. Your user has access to the machine's secrets
|
||||
3. The age key is available in the expected location
|
||||
|
||||
### Password Store Issues
|
||||
|
||||
**Symptom**: "pass: store not initialized"
|
||||
|
||||
**Solution**: Initialize password store:
|
||||
```bash
|
||||
export PASSWORD_STORE_DIR=/path/to/clan/vars
|
||||
pass init your-gpg-key
|
||||
```
|
||||
|
||||
## Getting Help
|
||||
|
||||
If these solutions don't resolve your issue:
|
||||
|
||||
1. Check the [clan-core issue tracker](https://git.clan.lol/clan/clan-core/issues)
|
||||
2. Ask in the Clan community channels
|
||||
3. Provide:
|
||||
- The generator configuration
|
||||
- The exact error message
|
||||
- Output of `clan --debug vars generate`
|
||||
Reference in New Issue
Block a user