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coder/docs/install/openshift.md
Eric Paulsen 39510f4163 docs: add openshift install (#6165)
* docs: add openshift install

* make: fmt

* Apply suggestions from code review

Update securityContext: set project-specific uid/gid, set readOnlyRootFilesystem=false

* add steps for creating compatible image and template

* Update docs/install/openshift.md

* make fmt

* docs: make changes on feedback

* combine helm steps

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Co-authored-by: Cian Johnston <cian@coder.com>
2023-03-20 03:48:53 -05:00

7.4 KiB

Requirements

Before proceeding, please ensure that you have an OpenShift cluster running K8s 1.19+ (OpenShift 4.7+) and have Helm 3.5+ installed. In addition, you'll need to install the OpenShift CLI (oc) to authenticate to your cluster and create OpenShift resources.

You'll also want to install the latest version of Coder locally in order to log in and manage templates.

Install Coder with OpenShift

1. Authenticate to OpenShift and create a Coder project

Run the following command to login to your OpenShift cluster:

oc login --token=w4r...04s --server=<cluster-url>

Next, you will run the below command to create a project for Coder:

oc new-project coder

2. Configure SecurityContext values

Depending upon your configured Security Context Constraints (SCC), you'll need to set the following securityContext values in the Coder Helm chart:

coder:
  securityContext:
    runAsNonRoot: true
    runAsUser: <project-specific UID>
    runAsGroup: <project-specific GID>
    readOnlyRootFilesystem: false

The above values are the Coder defaults. You will need to change these values in accordance with the applied SCC. Retrieve the project UID range with the following command:

oc get project coder -o json | jq -r '.metadata.annotations'
{
  "openshift.io/sa.scc.uid-range": "1000680000/10000"
}

3. Configure the Coder service, connection URLs, and cache values

To establish a connection to PostgreSQL, set the CODER_PG_CONNECTION_URL value. See our Helm documentation on configuring the PostgreSQL connection URL as a secret. Additionally, if accessing Coder over a hostname, set the CODER_ACCESS_URL value.

By default, Coder creates the cache directory in /home/coder/.cache. Given the OpenShift-provided UID, the Coder container does not have permission to write to this directory. To fix this, set the CODER_CACHE_DIRECTORY environment variable to /tmp/coder-cache.

Additionally, create the Coder service as a ClusterIP. In the next step, you will create an OpenShift route that points to the service HTTP target port.

coder:
  service:
    type: ClusterIP
  env:
    - name: CODER_CACHE_DIRECTORY
      value: /tmp/coder-cache
    - name: CODER_PG_CONNECTION_URL
      valueFrom:
        secretKeyRef:
          key: url
          name: coder-db-url
    - name: CODER_ACCESS_URL
      value: "https://coder-example.apps.openshiftapps.com"
  securityContext:
    runAsNonRoot: true
    runAsUser: <project-specific UID>
    runAsGroup: <project-specific GID>
    readOnlyRootFilesystem: false

Note: OpenShift provides a Developer Catalog offering you can use to install PostgreSQL into your cluster.

4. Create the OpenShift route

Below is the YAML spec for creating an OpenShift route that sends traffic to the HTTP port of the Coder service:

kind: Route
apiVersion: route.openshift.io/v1
metadata:
  namespace: coder
spec:
  host: https://coder-example.apps.openshiftapps.com
  to:
    kind: Service
    name: coder
  tls:
    # if set to edge, OpenShift will terminate TLS prior to the traffic reaching
    # the service.
    termination: edge
    # if set to Redirect, insecure client connections are redirected to the secure
    # port
    insecureEdgeTerminationPolicy: Redirect
  port:
    targetPort: http

Once complete, you can create this route in OpenShift via:

oc apply -f route.yaml

5. Install Coder

You can now install Coder using the values you've set from the above steps. To do so, run the series of helm commands below:

helm repo add coder-v2 https://helm.coder.com/v2
helm repo update
helm install coder coder-v2/coder \
  --namespace coder \
  --values values.yaml

6. Create an OpenShift-compatible image

While the deployment is spinning up, we will need to create some images that are compatible with OpenShift. These images can then be run without modifying the Security Context Constraints (SCCs) in OpenShift.

  1. Determine the UID range for the project:

    oc get project coder -o json | jq -r '.metadata.annotations'
    {
      "openshift.io/description": "",
      "openshift.io/display-name": "coder",
      "openshift.io/requester": "kube:admin",
      "openshift.io/sa.scc.mcs": "s0:c26,c15",
      "openshift.io/sa.scc.supplemental-groups": "1000680000/10000",
      "openshift.io/sa.scc.uid-range": "1000680000/10000"
    }
    

    Note the uid-range and supplemental-groups. In this case, the project coder has been allocated 10,000 UIDs starting at 1000680000, and 10,000 GIDs starting at 1000680000. In this example, we will pick UID and GID 1000680000.

  2. Create a BuildConfig referencing the source image you want to customize. This will automatically kick off a Build that will remain pending until step 3.

    For more information, please consult the OpenShift Documentation.

    oc create -f - <<EOF
    kind: BuildConfig
    apiVersion: build.openshift.io/v1
    metadata:
      name: enterprise-base
      namespace: coder
    spec:
      output:
        to:
          kind: ImageStreamTag
          name: 'enterprise-base:latest'
      strategy:
        type: Docker
        dockerStrategy:
          imageOptimizationPolicy: SkipLayers
      source:
        type: Dockerfile
        dockerfile: |
          # Specify the source image.
          FROM docker.io/codercom/enterprise-base:ubuntu
    
          # Switch to root
          USER root
    
          # As root:
          # 1) Remove the original coder user with UID 1000
          # 2) Add a coder group with an allowed UID
          # 3) Add a coder user as a member of the above group
          # 4) Fix ownership on the user's home directory
          RUN userdel coder && \
              groupadd coder -g 1000680000 && \
              useradd -l -u 1000680000 coder -g 1000680000 && \
              chown -R coder:coder /home/coder
    
          # Go back to the user 'coder'
          USER coder
      triggers:
        - type: ConfigChange
      runPolicy: Serial
    EOF
    
  3. Create an ImageStream as a target for the previous step:

    oc create imagestream enterprise-base
    

    The Build created in the previous step should now begin. Once completed, you should see output similar to the following:

    oc get imagestreamtag
    NAME                     IMAGE REFERENCE                                                                                                                                    UPDATED
    enterprise-base:latest   image-registry.openshift-image-registry.svc:5000/coder/enterprise-base@sha256:1dbbe4ee11be9218e1e4741264135a4f57501fe592d94d20db6bfe11692accd1   55 minutes ago
    

7. Create an OpenShift-compatible template

Start from the default "Kubernetes" template:

echo kubernetes | coderv2 templates init ./openshift-k8s
cd ./openshift-k8s

Edit main.tf and update the following fields of the Kubernetes pod resource:

  • spec.security_context: remove this field.
  • spec.container.image: update this field to the newly built image hosted on the OpenShift image registry from the previous step.
  • spec.container.security_context: remove this field.

Finally, create the template:

coder template create kubernetes -d .

This template should be ready to use straight away.