Synchronize Cluster Configuration using OpenShift Hive – SyncSets and SelectorSyncSets

It has been some time since my last post but I want to continue my OpenShift Hive article series about Getting started with OpenShift Hive and how to Deploy OpenShift/OKD 4.x clusters using Hive. In this blog post I want to explain how you can use Hive to synchronise cluster configuration using SyncSets. There are two different types of SyncSets, the SyncSet (namespaced custom resource), which you assign to a specific cluster name in the Cluster Deployment Reference, and a SelectorSyncSet (cluster-wide custom resource) using the Cluster Deployment Selector, which uses a label selector to apply configuration to a set of clusters matching the label across cluster namespaces.

Let’s look at the first example of a SyncSet (namespaced resource), which you can see in the example below. In the clusterDeploymentRefs you need to match a cluster name which is created in the same namespace where you create the SyncSet. In SyncSet there are sections where you can create resources or apply patches to a cluster. The last section is secretReference which you use to apply secrets to a cluster without having them in clear text written in the SyncSet:

apiVersion: hive.openshift.io/v1
kind: SyncSet
metadata:
  name: example-syncset
  namespace: okd
spec:
  clusterDeploymentRefs:
  - name: okd
  resources:
  - apiVersion: v1
    kind: Namespace
    metadata:
      name: myproject
  patches:
  - kind: Config
    apiVersion: imageregistry.operator.openshift.io/v1
    name: cluster
    applyMode: AlwaysApply
    patch: |-
      { "spec": { "defaultRoute": true }}
    patchType: merge
  secretReferences:
  - source:
      name: mysecret
      namespace: okd
    target:
      name: mysecret
      namespace: myproject

The second SyncSet example for an SelectorSyncSet (cluster-wide resource) is very similar to the previous example but more flexible because you can use a label selector clusterDeploymentSelector and the configuration can be applied to multiple clusters matching the label across cluster namespaces. Great use-case for common or environment configuration which is the same for all OpenShift clusters:

---
apiVersion: hive.openshift.io/v1
kind: SelectorSyncSet
metadata:
  name: mygroup
spec:
  resources:
  - apiVersion: v1
    kind: Namespace
    metadata:
      name: myproject
  resourceApplyMode: Sync
  clusterDeploymentSelector:
    matchLabels:
      cluster-group: okd

The problem with SyncSets is that they can get pretty large and it is complicated to write them by yourself depending on the size of configuration. My colleague Matt wrote a syncset generator which solves the problem and automatically generates a  SelectorSyncSet, please checkout his github repository:

$ wget -O syncset-gen https://github.com/matt-simons/syncset-gen/releases/download/v0.5/syncset-gen_linux_amd64 && chmod +x ./syncset-gen
$ sudo mv ./syncset-gen /usr/bin/
$ syncset-gen view -h
Parses a manifest directory and prints a SyncSet/SelectorSyncSet representation of the objects it contains.

Usage:
  ss view [flags]

Flags:
  -c, --cluster-name string   The cluster name used to match the SyncSet to a Cluster
  -h, --help                  help for view
  -p, --patches string        The directory of patch manifest files to use
  -r, --resources string      The directory of resource manifest files to use
  -s, --selector string       The selector key/value pair used to match the SelectorSyncSet to Cluster(s)

Next we need a repository to store the configuration for the OpenShift/OKD clusters. Below you can see a very simple example. The ./config folder contains common configuration which is using a SelectorSyncSet with a clusterDeploymentSelector:

$ tree
.
└── config
    ├── patch
    │   └── cluster-version.yaml
    └── resource
        └── namespace.yaml

To generate a SelectorSyncSet from the ./config folder, run the syncset-gen and the following command options:

$ syncset-gen view okd-cluster-group-selectorsyncset --selector cluster-group/okd -p ./config/patch/ -r ./config/resource/
{
    "kind": "SelectorSyncSet",
    "apiVersion": "hive.openshift.io/v1",
    "metadata": {
        "name": "okd-cluster-group-selectorsyncset",
        "creationTimestamp": null,
        "labels": {
            "generated": "true"
        }
    },
    "spec": {
        "resources": [
            {
                "apiVersion": "v1",
                "kind": "Namespace",
                "metadata": {
                    "name": "myproject"
                }
            }
        ],
        "resourceApplyMode": "Sync",
        "patches": [
            {
                "apiVersion": "config.openshift.io/v1",
                "kind": "ClusterVersion",
                "name": "version",
                "patch": "{\"spec\": {\"channel\": \"stable-4.3\",\"desiredUpdate\": {\"version\": \"4.3.0\", \"image\": \"quay.io/openshift-release-dev/[email protected]:3a516480dfd68e0f87f702b4d7bdd6f6a0acfdac5cd2e9767b838ceede34d70d\"}}}",
                "patchType": "merge"
            },
            {
                "apiVersion": "rbac.authorization.k8s.io/v1",
                "kind": "ClusterRoleBinding",
                "name": "self-provisioners",
                "patch": "{\"subjects\": null}",
                "patchType": "merge"
            }
        ],
        "clusterDeploymentSelector": {
            "matchExpressions": [
                {
                    "key": "cluster-group/okd",
                    "operator": "Exists"
                }
            ]
        }
    },
    "status": {}
}

To debug SyncSets use the below command in the cluster deployment namespace which can give you a status of whether the configuration has successfully applied or if it has failed to apply:

$ oc get syncsetinstance -n <namespace>
$ oc get syncsetinstances <synsetinstance name> -o yaml

I hope this was useful to get you started using OpenShift Hive and SyncSets to apply configuration to OpenShift/OKD clusters. More information about SyncSets can be found in the OpenShift Hive repository.

Getting started with OpenShift Hive

If you don’t know OpenShift Hive I recommend having a look at the video of my talk at RedHat OpenShift Commons about OpenShift Hive where I also talk about how you can provision and manage the lifecycle of OpenShift 4 clusters using the Kubernetes API and the OpenShift Hive operator.

The Hive operator has three main components the admission controller,  the Hive controller and the Hive operator itself. For more information about the Hive architecture visit the Hive docs:

You can use an OpenShift or native Kubernetes cluster to run the operator, in my case I use a EKS cluster. Let’s go through the prerequisites which are required to generate the manifests and the hiveutil:

$ curl -s "https://raw.githubusercontent.com/\
> kubernetes-sigs/kustomize/master/hack/install_kustomize.sh"  | bash
$ sudo mv ./kustomize /usr/bin/
$ wget https://dl.google.com/go/go1.13.3.linux-amd64.tar.gz
$ tar -xvf go1.13.3.linux-amd64.tar.gz
$ sudo mv go /usr/local

To setup the Go environment copy the content below and add to your .profile:

export GOPATH="${HOME}/.go"
export PATH="$PATH:/usr/local/go/bin"
export PATH="$PATH:${GOPATH}/bin:${GOROOT}/bin"

Continue with installing the Go dependencies and clone the OpenShift Hive Github repository:

$ mkdir -p ~/.go/src/github.com/openshift/
$ go get github.com/golang/mock/mockgen
$ go get github.com/golang/mock/gomock
$ go get github.com/cloudflare/cfssl/cmd/cfssl
$ go get github.com/cloudflare/cfssl/cmd/cfssljson
$ cd ~/.go/src/github.com/openshift/
$ git clone https://github.com/openshift/hive.git
$ cd hive/
$ git checkout remotes/origin/master

Before we run make deploy I would recommend modifying the Makefile that we only generate the Hive manifests without deploying them to Kubernetes:

$ sed -i -e 's#oc apply -f config/crds# #' -e 's#kustomize build overlays/deploy | oc apply -f -#kustomize build overlays/deploy > hive.yaml#' Makefile
$ make deploy
# The apis-path is explicitly specified so that CRDs are not created for v1alpha1
go run tools/vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd --apis-path=pkg/apis/hive/v1
CRD files generated, files can be found under path /home/ubuntu/.go/src/github.com/openshift/hive/config/crds.
go generate ./pkg/... ./cmd/...
hack/update-bindata.sh
# Deploy the operator manifests:
mkdir -p overlays/deploy
cp overlays/template/kustomization.yaml overlays/deploy
cd overlays/deploy && kustomize edit set image registry.svc.ci.openshift.org/openshift/hive-v4.0:hive=registry.svc.ci.openshift.org/openshift/hivev1:hive
kustomize build overlays/deploy > hive.yaml
rm -rf overlays/deploy

Quick look at the content of the hive.yaml manifest:

$ cat hive.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: hive
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: hive-operator
  namespace: hive

...

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    control-plane: hive-operator
    controller-tools.k8s.io: "1.0"
  name: hive-operator
  namespace: hive
spec:
  replicas: 1
  revisionHistoryLimit: 4
  selector:
    matchLabels:
      control-plane: hive-operator
      controller-tools.k8s.io: "1.0"
  template:
    metadata:
      labels:
        control-plane: hive-operator
        controller-tools.k8s.io: "1.0"
    spec:
      containers:
      - command:
        - /opt/services/hive-operator
        - --log-level
        - info
        env:
        - name: CLI_CACHE_DIR
          value: /var/cache/kubectl
        image: registry.svc.ci.openshift.org/openshift/hive-v4.0:hive
        imagePullPolicy: Always
        livenessProbe:
          failureThreshold: 1
          httpGet:
            path: /debug/health
            port: 8080
          initialDelaySeconds: 10
          periodSeconds: 10
        name: hive-operator
        resources:
          requests:
            cpu: 100m
            memory: 256Mi
        volumeMounts:
        - mountPath: /var/cache/kubectl
          name: kubectl-cache
      serviceAccountName: hive-operator
      terminationGracePeriodSeconds: 10
      volumes:
      - emptyDir: {}
        name: kubectl-cache

Now we can apply the Hive custom resource definition (crds):

$ kubectl apply -f ./config/crds/
customresourcedefinition.apiextensions.k8s.io/checkpoints.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterdeployments.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterdeprovisions.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterimagesets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterprovisions.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterstates.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/dnszones.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/hiveconfigs.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/machinepools.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/selectorsyncidentityproviders.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/selectorsyncsets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncidentityproviders.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncsets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncsetinstances.hive.openshift.io created

And continue to apply the hive.yaml manifest for deploying the OpenShift Hive operator and its components:

$ kubectl apply -f hive.yaml
namespace/hive created
serviceaccount/hive-operator created
clusterrole.rbac.authorization.k8s.io/hive-frontend created
clusterrole.rbac.authorization.k8s.io/hive-operator-role created
clusterrole.rbac.authorization.k8s.io/manager-role created
clusterrole.rbac.authorization.k8s.io/system:openshift:hive:hiveadmission created
rolebinding.rbac.authorization.k8s.io/extension-server-authentication-reader-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/auth-delegator-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/hive-frontend created
clusterrolebinding.rbac.authorization.k8s.io/hive-operator-rolebinding created
clusterrolebinding.rbac.authorization.k8s.io/hiveadmission-hive-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/hiveapi-cluster-admin created
clusterrolebinding.rbac.authorization.k8s.io/manager-rolebinding created
deployment.apps/hive-operator created

For the Hive admission controller you need to generate a SSL certifcate:

$ ./hack/hiveadmission-dev-cert.sh
~/Dropbox/hive/hiveadmission-certs ~/Dropbox/hive
2020/02/03 22:17:30 [INFO] generate received request
2020/02/03 22:17:30 [INFO] received CSR
2020/02/03 22:17:30 [INFO] generating key: ecdsa-256
2020/02/03 22:17:30 [INFO] encoded CSR
certificatesigningrequest.certificates.k8s.io/hiveadmission.hive configured
certificatesigningrequest.certificates.k8s.io/hiveadmission.hive approved
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
secret/hiveadmission-serving-cert created
~/Dropbox/hive

Afterwards we can check if all the pods are running, this might take a few seconds:

$ kubectl get pods -n hive
NAME                                READY   STATUS    RESTARTS   AGE
hive-controllers-7c6ccc84b9-q7k7m   1/1     Running   0          31s
hive-operator-f9f4447fd-jbmkh       1/1     Running   0          55s
hiveadmission-6766c5bc6f-9667g      1/1     Running   0          27s
hiveadmission-6766c5bc6f-gvvlq      1/1     Running   0          27s

The Hive operator is successfully installed on your Kubernetes cluster but we are not finished yet. To create the required Cluster Deployment manifests we need to generate the hiveutil binary:

$ make hiveutil
go generate ./pkg/... ./cmd/...
hack/update-bindata.sh
go build -o bin/hiveutil github.com/openshift/hive/contrib/cmd/hiveutil

To generate Hive Cluster Deployment manifests just run the following hiveutil command below, I output the definition with -o into yaml:

$ bin/hiveutil create-cluster --base-domain=mydomain.example.com --cloud=aws mycluster -o yaml
apiVersion: v1
items:
- apiVersion: hive.openshift.io/v1
  kind: ClusterImageSet
  metadata:
    creationTimestamp: null
    name: mycluster-imageset
  spec:
    releaseImage: quay.io/openshift-release-dev/ocp-release:4.3.2-x86_64
  status: {}
- apiVersion: v1
  kind: Secret
  metadata:
    creationTimestamp: null
    name: mycluster-aws-creds
  stringData:
    aws_access_key_id: <-YOUR-AWS-ACCESS-KEY->
    aws_secret_access_key: <-YOUR-AWS-SECRET-KEY->
  type: Opaque
- apiVersion: v1
  data:
    install-config.yaml: <-BASE64-ENCODED-OPENSHIFT4-INSTALL-CONFIG->
  kind: Secret
  metadata:
    creationTimestamp: null
    name: mycluster-install-config
  type: Opaque
- apiVersion: hive.openshift.io/v1
  kind: ClusterDeployment
  metadata:
    creationTimestamp: null
    name: mycluster
  spec:
    baseDomain: mydomain.example.com
    clusterName: mycluster
    controlPlaneConfig:
      servingCertificates: {}
    installed: false
    platform:
      aws:
        credentialsSecretRef:
          name: mycluster-aws-creds
        region: us-east-1
    provisioning:
      imageSetRef:
        name: mycluster-imageset
      installConfigSecretRef:
        name: mycluster-install-config
  status:
    clusterVersionStatus:
      availableUpdates: null
      desired:
        force: false
        image: ""
        version: ""
      observedGeneration: 0
      versionHash: ""
- apiVersion: hive.openshift.io/v1
  kind: MachinePool
  metadata:
    creationTimestamp: null
    name: mycluster-worker
  spec:
    clusterDeploymentRef:
      name: mycluster
    name: worker
    platform:
      aws:
        rootVolume:
          iops: 100
          size: 22
          type: gp2
        type: m4.xlarge
    replicas: 3
  status:
    replicas: 0
kind: List
metadata: {}

I hope this post is useful in getting you started with OpenShift Hive. In my next article I will go through the details of the OpenShift 4 cluster deployment with Hive.

Read my new article about OpenShift / OKD 4.x Cluster Deployment using OpenShift Hive

OpenShift Hive – API driven OpenShift cluster provisioning and management operator

RedHat invited me and my colleague Matt to speak at RedHat OpenShift Commons in London about the API driven OpenShift cluster provisioning and management operator called OpenShift Hive. We have been using OpenShift Hive for the past few months to provision and manage the OpenShift 4 estate across multiple environments. Below the video recording of our talk at OpenShift Commons London:

The Hive operator requires to run on a separate Kubernetes cluster to centrally provision and manage the OpenShift 4 clusters. With Hive you can manage hundreds of cluster deployments and configuration with a single operator. There is nothing required on the OpenShift 4 clusters itself, Hive only requires access to the cluster API:

The ClusterDeployment custom resource is the definition for the cluster specs, similar to the openshift-installer install-config where you define cluster specifications, cloud credential and image pull secrets. Below is an example of the ClusterDeployment manifest:

---
apiVersion: hive.openshift.io/v1
kind: ClusterDeployment
metadata:
  name: mycluster
  namespace: mynamespace
spec:
  baseDomain: hive.example.com
  clusterName: mycluster
  platform:
    aws:
      credentialsSecretRef:
        name: mycluster-aws-creds
      region: eu-west-1
  provisioning:
    imageSetRef:
      name: openshift-v4.3.0
    installConfigSecretRef:
      name: mycluster-install-config
    sshPrivateKeySecretRef:
      name: mycluster-ssh-key
  pullSecretRef:
    name: mycluster-pull-secret

The SyncSet custom resource is defining the configuration and is able to regularly reconcile the manifests to keep all clusters synchronised. With SyncSets you can apply resources and patches as you see in the example below:

---
apiVersion: hive.openshift.io/v1
kind: SyncSet
metadata:
  name: mygroup
spec:
  clusterDeploymentRefs:
  - name: ClusterName
  resourceApplyMode: Upsert
  resources:
  - apiVersion: user.openshift.io/v1
    kind: Group
    metadata:
      name: mygroup
    users:
    - myuser
  patches:
  - kind: ConfigMap
    apiVersion: v1
    name: foo
    namespace: default
    patch: |-
      { "data": { "foo": "new-bar" } }
    patchType: merge
  secretReferences:
  - source:
      name: ad-bind-password
      namespace: default
    target:
      name: ad-bind-password
      namespace: openshift-config

Depending of the amount of resource and patches you want to apply, a SyncSet can get pretty large and is not very easy to manage. My colleague Matt wrote a SyncSet Generator, please check this Github repository.

In one of my next articles I will go into more detail on how to deploy OpenShift Hive and I’ll provide more examples of how to use ClusterDeployment and SyncSets. In the meantime please check out the OpenShift Hive repository for more details, additionally here are links to the Hive documentation on using Hive and Syncsets.

Read my new article about installing OpenShift Hive.