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@ -1,13 +1,16 @@
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# systemd-vaultd
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# systemd-vaultd - load vault credentials with systemd units
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systemd-vaultd is a proxy between systemd and [vault
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agent](https://vaultproject.io). It provides a unix socket that can be used in
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systemd services in the `LoadCredential` option and then waits for vault agent
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to write these secrets at `/run/systemd-vaultd/<service_name>-<secret_name>`.
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> Mostly written in a train
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- Jörg Thalheim
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## Systemd's `LoadCredential` option
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This project's goal is to simplify the loading of [HashiCorp
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Vault](https://www.vaultproject.io/) secrets from
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[systemd](https://systemd.io/) units.
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Systemd has an option called `LoadCredentials` that allows to provide credentials to a service:
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## Problem statement
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Systemd has an option called `LoadCredentials` that allows to provide
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credentials to a service:
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```conf
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# myservice.service
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@ -16,15 +19,28 @@ ExecStart=/usr/bin/myservice.sh
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LoadCredential=foobar:/etc/myfoobarcredential.txt
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```
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In this case systemd will load credential the file `/etc/myfoobarcredential.txt`
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and provide it to the service at `$CREDENTIAL_PATH/foobar`.
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In this case systemd will load credential the file
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`/etc/myfoobarcredential.txt` and provide it to the service at
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`$CREDENTIAL_PATH/foobar`.
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It's handy because it bypasses file permission issues.
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/etc/myfoobarcredential.txt can be owned by root, and the unit run as a
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different or dynamic user.
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While vault agent also supports writing these secrets, a major issue is that
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the consumer service may be started before vault agent was able to retrieve
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secrets from vault. In that case, systemd would fail to start the service.
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While vault agent also supports writing these secrets, a service may be started
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before vault agent was able to retrieve secrets from vault, in which case
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systemd would fail to start the service.
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## The solution
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Here is where `systemd-vaultd` is put to use: In additional to normal paths,
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systemd also supports loading credentials from unix sockets.
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In order to do so, I wrote a `systemd-vaultd` service which acts as a proxy
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between systemd and vault agent that is running on the machine. It provides a
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unix socket that can be used in systemd services in the `LoadCredential`
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option and then waits for vault agent to write these secrets at
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`/run/systemd-vaultd/<service_name>-<secret_name>`.
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We take advantage that in addition to normal paths, systemd also supports
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loading credentials from unix sockets.
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With `systemd-vaultd` the service `myservice.service` would look like this:
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@ -43,17 +59,34 @@ template {
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}
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```
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When `myservice` is started, systemd will open a connection to `systemd-vaultd`'s socket.
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`systemd-vaultd` then either serve the secrets from `/run/systemd-vaultd/secrets/myservice.service-foo`
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or it waits with inotify on secret directory for vault agent to write the secret.
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When `myservice` is started, systemd will open a connection to
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`systemd-vaultd`'s socket. `systemd-vaultd` then either serve the secrets
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from `/run/systemd-vaultd/secrets/myservice.service-foo` or it waits with
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inotify on secret directory for vault agent to write the secret.
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⋈
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## Installation
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The installation requires a `go` compiler and `make` to be installed.
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This command will install the `systemd-vaultd` binary to `/usr/bin/systemd-vaultd` as well
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as installing a following systemd unit files: `systemd-vaultd.service`, `systemd-vaultd.socket`:
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This command will install the `systemd-vaultd` binary to
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`/usr/bin/systemd-vaultd` as well as installing a following systemd unit
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files: `systemd-vaultd.service`, `systemd-vaultd.socket`:
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```shell
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make install
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```
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## License
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Copyright (c) 2022 [Jörg Thalheim](https://github.com/mic92) and contributors.
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This project is free software, and may be redistributed under the terms
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specified in the [LICENSE](LICENSE) file.
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## About
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This project is maintained by Numtide.
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Need help or support? [Contact us](https://numtide.com/contact)
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zimbatm
2 years ago