GitOps workloads on infrastructure nodes
Running GitOps control plane workloads on infrastructure nodes
Abstract
Chapter 1. Running GitOps control plane workloads on infrastructure nodes
You can use infrastructure nodes to isolate infrastructure workloads for two primary purposes:
- To prevent billing costs associated with the number of subscriptions
- To separate maintenance and management
You can use the OpenShift Container Platform to run GitOps control plane workloads on infrastructure nodes. This includes the Operator pod and the control plane workloads created by the Red Hat OpenShift GitOps Operator in the openshift-gitops
namespace by default, including the default Argo CD instance in this namespace.
With GitOps control plane workloads, you can securely and declaratively isolate the infrastructure workloads by creating multiple isolated Argo CD instances in a cluster, with full control over what an Argo CD instance is capable of. In addition, you can manage these Argo CD instances declaratively across multiple developer namespaces. By using taints, you can ensure that only infrastructure components run on these nodes.
All other Argo CD instances installed in user namespaces are not eligible to run on infrastructure nodes.
1.1. Moving GitOps control plane workloads to infrastructure nodes
You can move the GitOps control plane workloads installed by the Red Hat OpenShift GitOps to the infrastructure nodes. The following are the control plane workloads that you can move:
-
kam deployment
-
cluster deployment
(backend service) -
openshift-gitops-applicationset-controller deployment
-
openshift-gitops-dex-server deployment
-
openshift-gitops-redis deployment
-
openshift-gitops-redis-ha-haproxy deployment
-
openshift-gitops-repo-sever deployment
-
openshift-gitops-server deployment
-
openshift-gitops-application-controller statefulset
-
openshift-gitops-redis-server statefulset
Procedure
Label existing nodes as infrastructure by running the following command:
$ oc label node <node-name> node-role.kubernetes.io/infra=
Edit the
GitOpsService
custom resource (CR) to add the infrastructure node selector:$ oc edit gitopsservice -n openshift-gitops
In the
GitOpsService
CR file, addrunOnInfra
field to thespec
section and set it totrue
. This field moves the control plane workloads inopenshift-gitops
namespace to the infrastructure nodes:apiVersion: pipelines.openshift.io/v1alpha1 kind: GitopsService metadata: name: cluster spec: runOnInfra: true
Optional: Apply taints and isolate the workloads on infrastructure nodes and prevent other workloads from scheduling on these nodes.
$ oc adm taint nodes -l node-role.kubernetes.io/infra infra=reserved:NoSchedule infra=reserved:NoExecute
Optional: If you apply taints to the nodes, you can add tolerations in the
GitOpsService
CR:spec: runOnInfra: true tolerations: - effect: NoSchedule key: infra value: reserved - effect: NoExecute key: infra value: reserved
To verify that the workloads are scheduled on infrastructure nodes in the Red Hat OpenShift GitOps namespace, click any of the pod names and ensure that the Node selector and Tolerations have been added.
Any manually added Node selectors and Tolerations in the default Argo CD CR will be overwritten by the toggle and the tolerations in the GitOpsService
CR.
1.2. Moving the GitOps Operator pod to infrastructure nodes
You can move the GitOps Operator pod to the infrastructure nodes.
Prerequisites
- You have installed the Red Hat OpenShift GitOps Operator on your OpenShift Container Platform cluster.
-
You have access to the cluster with
cluster-admin
privileges.
Procedure
Label an existing node as infrastructure node by running the following command:
$ oc label node <node_name> node-role.kubernetes.io/infra= 1
- 1
- Replace <node_name> with the name of the node you want to label as infrastructure node.
Example output
node/<node_name> labeled
Edit the Red Hat OpenShift GitOps
Subscription
resource by running the following command:$ oc -n openshift-gitops-operator edit subscription openshift-gitops-operator
Add
nodeSelector
andtolerations
to thespec.config
field in theSubscription
resource:Example Subscription
apiVersion: operators.coreos.com/v1alpha1 kind: Subscription metadata: name: openshift-gitops-operator namespace: openshift-gitops-operator spec: config: nodeSelector: 1 node-role.kubernetes.io/infra: "" tolerations: 2 - key: node-role.kubernetes.io/infra operator: Exists effect: NoSchedule
Example output
subscription.operators.coreos.com/openshift-gitops-operator edited
Verify that the GitOps Operator pod is running on the infrastructure node by running the following command:
$ oc -n openshift-gitops-operator get po -owide
Example output
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES openshift-gitops-operator-controller-manager-abcd 2/2 Running 0 11m 94.142.44.126 <node_name> <none> <none> 1
- 1
- Ensure that the listed
<node_name>
is the node with thenode-role.kubernetes.io/infra
label.
1.3. Additional resources
- For more information about taints and tolerations, see Controlling pod placement using node taints.
- For more information about infrastructure machine sets, see Creating infrastructure machine sets.