External provisioners

By default, the Coder server runs built-in provisioner daemons, which execute terraform during workspace and template builds. However, there are sometimes benefits to running external provisioner daemons:

• Secure build environments: Run build jobs in isolated containers, preventing malicious templates from gaining shell access to the Coder host.

• Isolate APIs: Deploy provisioners in isolated environments (on-prem, AWS, Azure) instead of exposing APIs (Docker, Kubernetes, VMware) to the Coder server. See Provider Authentication for more details.

• Isolate secrets: Keep Coder unaware of cloud secrets, manage/rotate secrets on provisioner servers.

• Reduce server load: External provisioners reduce load and build queue times from the Coder server. See Scaling Coder for more details.

Each provisioner can run a single concurrent workspace build. For example, running 30 provisioner containers will allow 30 users to start workspaces at the same time.

Provisioners are started with the coder provisionerd start command.

Authentication

The provisioner daemon must authenticate with your Coder deployment.

Set a provisioner daemon pre-shared key (PSK) on the Coder server and start the provisioner with coder provisionerd start --psk <your-psk>. If you are installing with Helm, see the Helm example below.

Coder still supports authenticating the provisioner daemon with a token from a user with the Template Admin or Owner role. This method is deprecated in favor of the PSK, which only has permission to access provisioner daemon APIs. We recommend migrating to the PSK as soon as practical.

Types of provisioners

Provisioners can broadly be categorized by scope: organization or user. The scope of a provisioner can be specified with -tag=scope=<scope> when starting the provisioner daemon. Only users with at least the Template Admin role or higher may create organization-scoped provisioner daemons.

There are two exceptions:

• Built-in provisioners are always organization-scoped.
• External provisioners started using a pre-shared key (PSK) are always organization-scoped.

Organization-Scoped Provisioners

Organization-scoped Provisioners can pick up build jobs created by any user. These provisioners always have the implicit tags scope=organization owner="".

coder provisionerd start

User-scoped Provisioners

User-scoped Provisioners can only pick up build jobs created from user-tagged templates. Unlike the other provisioner types, any Coder user can run user provisioners, but they have no impact unless there exists at least one template with the scope=user provisioner tag.

coder provisionerd start \
  --tag scope=user

# In another terminal, create/push
# a template that requires user provisioners
coder templates push on-prem \
  --provisioner-tag scope=user

Provisioner Tags

You can use provisioner tags to control which provisioners can pick up build jobs from templates (and corresponding workspaces) with matching explicit tags.

Provisioners have two implicit tags: scope and owner. Coder sets these tags automatically.

• Organization-scoped provisioners always have the implicit tags scope=organization owner=""
• User-scoped provisioners always have the implicit tags scope=user owner=<uuid>

For example:

# Start a provisioner with the explicit tags
# environment=on_prem and datacenter=chicago
coder provisionerd start \
  --tag environment=on_prem \
  --tag datacenter=chicago

# In another terminal, create/push
# a template that requires the explicit
# tag environment=on_prem
coder templates push on-prem \
  --provisioner-tag environment=on_prem

# Or, match the provisioner's explicit tags exactly
coder templates push on-prem-chicago \
  --provisioner-tag environment=on_prem \
  --provisioner-tag datacenter=chicago

A provisioner can run a given build job if one of the below is true:

1. A job with no explicit tags can only be run on a provisioner with no explicit tags. This way you can introduce tagging into your deployment without disrupting existing provisioners and jobs.
2. If a job has any explicit tags, it can only run on a provisioner with those explicit tags (the provisioner could have additional tags).

The external provisioner in the above example can run build jobs with tags:

• environment=on_prem
• datacenter=chicago
• environment=on_prem datacenter=chicago

However, it will not pick up any build jobs that do not have either of the environment or datacenter tags set. It will also not pick up any build jobs from templates with the tag scope=user set.

This is illustrated in the below table:

Note to maintainers: to generate this table, run the following command and copy the output:

go test -v -count=1 ./coderd/provisionerdserver/ -test.run='^TestAcquirer_MatchTags/GenTable$'

Example: Running an external provisioner with Helm

Coder provides a Helm chart for running external provisioner daemons, which you will use in concert with the Helm chart for deploying the Coder server.

1. Create a long, random pre-shared key (PSK) and store it in a Kubernetes secret

   kubectl create secret generic coder-provisioner-psk --from-literal=psk=`head /dev/urandom | base64 | tr -dc A-Za-z0-9 | head -c 26`
   

2. Modify your Coder values.yaml to include

   provisionerDaemon:
     pskSecretName: "coder-provisioner-psk"
   

3. Redeploy Coder with the new values.yaml to roll out the PSK. You can omit --version <your version> to also upgrade Coder to the latest version.

   helm upgrade coder coder-v2/coder \
       --namespace coder \
       --version <your version> \
       --values values.yaml
   

4. Create a provisioner-values.yaml file for the provisioner daemons Helm chart. For example

   coder:
     env:
       - name: CODER_URL
         value: "https://coder.example.com"
     replicaCount: 10
   provisionerDaemon:
     pskSecretName: "coder-provisioner-psk"
     tags:
       location: auh
       kind: k8s
   

   This example creates a deployment of 10 provisioner daemons (for 10 concurrent builds) with the listed tags. For generic provisioners, remove the tags.

   Refer to the values.yaml file for the coder-provisioner chart for information on what values can be specified.

5. Install the provisioner daemon chart

   helm install coder-provisioner coder-v2/coder-provisioner \
       --namespace coder \
       --version <your version> \
       --values provisioner-values.yaml
   

   You can verify that your provisioner daemons have successfully connected to Coderd by looking for a debug log message that says provisionerd: successfully connected to coderd from each Pod.

Example: Running an external provisioner on a VM

curl -L https://coder.com/install.sh | sh
export CODER_URL=https://coder.example.com
export CODER_SESSION_TOKEN=your_token
coder provisionerd start

Example: Running an external provisioner via Docker

docker run --rm -it \
  -e CODER_URL=https://coder.example.com/ \
  -e CODER_SESSION_TOKEN=your_token \
  --entrypoint /opt/coder \
  ghcr.io/coder/coder:latest \
  provisionerd start

Disable built-in provisioners

As mentioned above, the Coder server will run built-in provisioners by default. This can be disabled with a server-wide flag or environment variable.

coder server --provisioner-daemons=0

Prometheus metrics

Coder provisioner daemon exports metrics via the HTTP endpoint, which can be enabled using either the environment variable CODER_PROMETHEUS_ENABLE or the flag --prometheus-enable.

The Prometheus endpoint address is http://localhost:2112/ by default. You can use either the environment variable CODER_PROMETHEUS_ADDRESS or the flag --prometheus-address <network-interface>:<port> to select a different listen address.

If you have provisioners daemons deployed as pods, it is advised to monitor them separately.