GitOps for k8s
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standalone-setup.md 7.1KB


title: Customising the deployment

menu_order: 20

Customising the daemon configuration

The deployment installs Flux and its dependencies. First, change to the directory with the examples configuration.

Connect Flux to a repository

First, you need to connect Flux to the repository with Kubernetes manifests. This is achieved by setting the --git-url and --git-branch arguments in the flux-deployment.yaml manifest.

Flux deployment

You will need to create a secret in which Flux will store its SSH key. The daemon won’t start without this present.

The flux logs should show that it has now connected to the repository and synchronised the cluster.

When using Kubernetes, this key is stored as a Kubernetes secret. You can restart flux and it will continue to use the same key.

Add an SSH deploy key to the repository

Flux connects to the repository using an SSH key.

The SSH key must be configured to have R/W access to the repository.

More specifically, in the case of standalone Flux, the ssh key must be able to create and update tags. E.g. in Gitlab, that means it requires Maintainer permissions. The Developer permission can create tags, but not update them.

You have two options:

1. Allow Flux to generate a key for you.

If you don’t specify a key to use, Flux will create one for you. Obtain the public key through fluxctl:

fluxctl identity

2. Specify a key to use

Create a Kubernetes Secret from a private key:

kubectl create secret generic flux-git-deploy --from-file=identity=/full/path/to/private_key

this will result in a secret that has the structure:

  apiVersion: v1
  data:
    identity: <base64 encoded RSA PRIVATE KEY>
  kind: Secret
  type: Opaque
  metadata:
    ...

The Kubernetes deployment configuration file flux-deployment.yaml runs the Flux daemon, but you’ll need to edit it first, at least to supply your own configuration repo (the --git-repo argument).

$EDITOR flux-deployment.yaml
kubectl create -f flux-deployment.yaml

Note for Kubernetes >=1.6 with role-based access control (RBAC)

You will need to provide fluxd with a service account which can access the namespaces you want to use Flux with. To do this, consult the example service account given in flux-account.yaml (which puts essentially no constraints on the account) and the RBAC documentation, and create a service account in whichever namespace you put fluxd in. You may need to alter the namespace: default lines, if you adapt the example.

Using an SSH key allows you to maintain control of the repository. You can revoke permission for flux to access the repository at any time by removing the deploy key.

Using a private git host

If you’re using your own git host -- e.g., your own installation of gitlab, or bitbucket server -- you will need to add its host key to ~/.ssh/known_hosts in the Flux daemon container.

First, run a check that you can clone the repo. The following assumes that your git server’s hostname (e.g., githost) is in $GITHOST and the URL you’ll use to access the repository (e.g., user@githost:path/to/repo) is in $GITREPO.

$ # Find the fluxd daemon pod:
$ kubectl get pods --all-namespaces -l name=flux
NAMESPACE   NAME                    READY     STATUS    RESTARTS   AGE
weave       flux-85cdc6cdfc-n2tgf   1/1       Running   0          1h

$ kubectl exec -n weave flux-85cdc6cdfc-n2tgf -ti -- \
    env GITHOST="$GITHOST" GITREPO="$GITREPO" PS1="container$ " /bin/sh

container$ git clone $GITREPO
Cloning into <repository name>...
No ECDSA host key is known for  <GITHOST> and you have requested strict checking.
Host key verification failed.
fatal: Could not read from remote repository

container$ # ^ that was expected. Now we'll try with a modified known_hosts
container$ ssh-keyscan $GITHOST >> ~/.ssh/known_hosts
container$ git clone $GITREPO
Cloning into '...'
...

If git clone doesn’t succeed, you’ll need to check that the SSH key has been installed properly first, then come back. ssh -vv $GITHOST from within the container may help debug it.

If it did work, you will need to make it a more permanent arrangement. Back in that shell, create a configmap for the cluster. To make sure the configmap is created in the namespace of the Flux or weave deployment, the namespace is set explicitly:

container$ kubectl create configmap flux-ssh-config --from-file=$HOME/.ssh/known_hosts -n $(cat /var/run/secrets/kubernetes.io/serviceaccount/namespace)
configmap "flux-ssh-config" created

To use the ConfigMap every time the Flux daemon restarts, you’ll need to mount it into the container. The example deployment manifest includes an example of doing this, commented out. Uncomment those two blocks:

      - name: ssh-config
        configMap:
          name: flux-ssh-config
        - name: ssh-config
          mountPath: /root/.ssh

It assumes you used flux-ssh-config as name of the ConfigMap and then reapply the manifest.

Another alternative is to create the configmap from a template. This could be something like:

apiVersion: v1
data:
  known_hosts: |
    # github
    192.30.253.112 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==
    # github
    192.30.253.113 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==
    # private gitlab
    gitlab.________ ssh-rsa AAAAB3N...
kind: ConfigMap
metadata:
  name: flux-ssh-config
  namespace: <OPTIONAL NAMESPACE (if not default)>

You will need to explicitly tell fluxd to use that service account by uncommenting and possible adapting the line # serviceAccountName: flux in the file fluxd-deployment.yaml before applying it.

Memcache

Flux uses memcache to cache docker registry requests.

kubectl create -f memcache-dep.yaml -f memcache-svc.yaml