Setting up Red Hat Advanced Cluster Management for Kubernetes on CodeReady Containers (CRC) Using Minikube and Minishift as Managed Clusters

2020년 9월 16일Christian Stark16분 읽기
하이브리드 클라우드

Learn to install Red Hat Advanced Cluster Management for Kubernetes on CodeReady Containers (CRC), and to create two additional Kubernetes-Demo-Clusters on the same Virtual Machine (VM) to import into Red Hat Advanced Cluster Management. In this example, we use a Red Hat Enterprise Linux (RHEL) 8.2 VM with 128 GB. The following example in this blog is for flexible and cost-efficient test, and demo-environments. This demonstration can only be used in enterprise-environments.

You can use scripts to setup a CRC with Red Hat Advanced Cluster Management from this repository.

Prerequisites:

Installing CRC

Complete the following steps to download and install Red Hat CRC:

  1. Install the required software packages for Red Hat CRC. Run the following command:

    dnf install wget git qemu-kvm qemu-img libvirt virt-install libvirt-client

  2. Run the following commands to prepare the set up for Red Hat CRC:

    su - kni

    mkdir ~/crc

    wget https://mirror.openshift.com/pub/openshift-v4/clients/crc/latest/crc-linux-amd64.tar.xz

    tar -xvf crc-linux-amd64.tar.xz

    mv ~/crc-linux-1.15.0-amd64/* ~/crc

    cd ~/crc

    chmod +x crc

  3. Add the CRC to your PATH by running the following command:

    export PATH=$PATH:~/crc

  4. Download the pull secret and setup CRC by running the following commands:

    crc setup

    crc config set cpus 16

    crc config set memory 64000

    crc config set pull-secret-file pull-secret

Verify CRC installation

Complete the following steps to verify that your Red Hat CRC is installed and configured:

  1. Run the following command to start the CRC virtual machine which represents the OpenShift cluster:

    crc start

  2. Access your OpenShift cluster by running the following commands:

    eval $(crc oc-env)

    oc login -u kubeadmin -p $(crc console --credentials | awk -F "kubeadmin" '{print $2}' | cut -c 5- | rev | cut -c31- | rev) https://api.crc.testing:6443

Install Red Hat Advanced Cluster Management for Kubernetes

Now we can install Red Hat Advanced Cluster Management for Kubernetes by completing the following steps. View the following sections for more details on the installation process.

  1. Clone the acminstall repository and install Red Hat Advanced Cluster Management for Kubernetes:

    git clone https://github.com/ch-stark/acminstall

    cd acminstall/rhacmv2

  2. Apply the install to the open-cluster-management namespace with the following command:

    oc apply -f v2_namespace.yaml -n open-cluster-management

  3. You need to create a secret from the downloaded pull secret and add it into the appropriate namespace. Run the following command:

    oc create secret generic pull-secret -n open-cluster-management --from-file=.dockerconfigjson=../../pull-secret --type=kubernetes.io/dockerconfigjson

  4. Create and apply an OperatorGroup and Subscription to Red Hat Advanced Cluster Management with the following commands:

    oc apply -f v2_operatorgroup.yaml -n open-cluster-management
    oc apply -f v2_subscription.yaml  -n open-cluster-management

  5. Verify that your pods are functional by running the following command:

    oc get pods -n open-cluster-management

    Your results might resemble the following content:

    NAME                                                              READY   STATUS    RESTARTS   AGE
    cluster-manager-5cbcc76654-4qp6x                                  1/1     Running   0          75s
    cluster-manager-5cbcc76654-gnjbn                                  1/1     Running   0          40s
    cluster-manager-5cbcc76654-wp8b5                                  1/1     Running   0          55s
    hive-operator-7449bc7ff4-c2qsc                                    1/1     Running   0          75s
    multicluster-operators-application-7dc7755dcf-9lgkk               4/4     Running   0          74s
    multicluster-operators-hub-subscription-5b798f6b6d-lwfzk          1/1     Running   0          74s
    multicluster-operators-standalone-subscription-78d4bf8d6c-s29qb   1/1     Running   0          74s
    multiclusterhub-operator-5fbcf8cc49-mk9wv                         1/1     Running   0          75s

  6. Apply the Operator-CRD by running the following command:

    oc apply -f v2_multiclusterhub.yaml -n open-cluster-management

    The Operator YAML file might resemble the following content:

    apiVersion: operator.open-cluster-management.io/v1
    kind: MultiClusterHub
    metadata:
      name: multiclusterhub
    spec:
      availabilityConfig: High
      hive:
        backup:
          velero: {}
        failedProvisionConfig: {}
      imagePullSecret: pull-secret
      ingress:
        sslCiphers:
          - ECDHE-ECDSA-AES256-GCM-SHA384
          - ECDHE-RSA-AES256-GCM-SHA384
          - ECDHE-ECDSA-CHACHA20-POLY1305
          - ECDHE-RSA-CHACHA20-POLY1305
          - ECDHE-ECDSA-AES128-GCM-SHA256
          - ECDHE-RSA-AES128-GCM-SHA256
      overrides: {}
      separateCertificateManagement: false

  7. Verify which pods are functional by running the following commands:

    oc get pods -n open-cluster-management
    oc get pods -n open-cluster-management-hub
    oc get pods -n hive

    Your results might resemble the following content:

    NAMESPACE                                          NAME                                                              READY   STATUS        RESTARTS   AGE
    hive                                               hive-controllers-b98849fc8-mbf6t                                  1/1     Running       0          3h9m
    hive                                               hiveadmission-6854b49659-4w4f4                                    1/1     Running       0          81m
    hive                                               hiveadmission-6854b49659-rw2b7                                    1/1     Running       0          81m
    open-cluster-management-hub                        cluster-manager-registration-controller-65f86d66dc-4hl45          1/1     Running       0          3h9m
    open-cluster-management-hub                        cluster-manager-registration-controller-65f86d66dc-6stxv          1/1     Running       0          3h9m
    open-cluster-management-hub                        cluster-manager-registration-controller-65f86d66dc-ksx45          1/1     Running       0          3h9m
    open-cluster-management-hub                        cluster-manager-registration-webhook-5ff66dc4c9-hlt67             1/1     Running       0          3h9m
    open-cluster-management-hub                        cluster-manager-registration-webhook-5ff66dc4c9-nwhx9             1/1     Running       0          3h9m
    open-cluster-management-hub                        cluster-manager-registration-webhook-5ff66dc4c9-rpw2p             1/1     Running       0          3h9m
    open-cluster-management                            application-chart-7cc65-applicationui-7f959f4d7f-phd8p            1/1     Running       0          3h7m
    open-cluster-management                            application-chart-7cc65-applicationui-7f959f4d7f-xx8dk            1/1     Running       0          3h7m
    open-cluster-management                            cert-manager-1d535-5dc95c59f6-88hlm                               1/1     Running       0          3h10m
    open-cluster-management                            cert-manager-1d535-5dc95c59f6-qbtph                               1/1     Running       0          3h10m
    open-cluster-management                            cert-manager-webhook-b697c47bb-8kzxs                              1/1     Running       0          76m
    open-cluster-management                            cert-manager-webhook-b697c47bb-ff5nh                              1/1     Running       0          76m
    open-cluster-management                            cert-manager-webhook-fafb4-cainjector-6ff887db4d-d6tn5            1/1     Running       1          3h8m
    open-cluster-management                            cert-manager-webhook-fafb4-cainjector-6ff887db4d-z4zlr            1/1     Running       1          3h8m
    ...

Note: When you work from a remote-computer and want to access a CRC from a browser, it might be helpful to set up a VNCServer. I recommend that you review the Install VNC server on CentOS 8/RHEL 8 blog for more tips.

Add a minikube-managed cluster

Add a Minikube cluster to run Kubernetes locally. For more information, see Kuberentes Using Minikube to Create a Cluster. The minikube-managed cluster can communicate with the hub cluster. Complete the following steps to add a minikube-managed cluster to the hub cluster:

  1. Install Minikube with the following commands:

    curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 \
    && chmod +x minikube

    sudo mkdir -p /usr/local/bin/
    sudo install minikube /usr/local/bin/

  2. Open firewall ports to monitor network traffic and restart your Daemon service. Run the following commands:


    sudo firewall-cmd --permanent --zone=trusted --change-interface=virbr0

    sudo firewall-cmd --permanent --zone=trusted --add-port=6443/tcp

    sudo firewall-cmd --reload

    sudo service libvirtd restart

  3. Start and configure Minikube. Run the following commands:


    ## start minikube with kvm2 driver
    minikube start --memory=12000 --cpus=12 --kubernetes-version="v1.18.3" --driver=kvm2 -p minikube

    # set the context
    kubectl config use-context minikube

    # search for configmap
    kubectl edit cm coredns --namespace kube-system

    # change it and add crc.testing 
    data:
      Corefile: |
        .:53 {
            errors
            health {
                lameduck 5s
            }

            ready
            kubernetes cluster.local in-addr.arpa ip6.arpa {
                pods insecure
                fallthrough in-addr.arpa ip6.arpa
                ttl 30
            }
            prometheus :9153
            forward . /etc/resolv.conf
            cache 30
            loop
            reload
            loadbalance
        }
        crc.testing {
          hosts {
              192.168.130.11 api.crc.testing
          }
        }

    • Verify that the pods are running with the following command:

      kubectl get  pods  --namespace kube-system

      NAME                               READY   STATUS    RESTARTS   AGE
      coredns-66bff467f8-l6dzl           1/1     Running   0          175m
      coredns-66bff467f8-r78th           1/1     Running   0          175m
      etcd-minikube                      1/1     Running   0          175m
      kube-apiserver-minikube            1/1     Running   0          175m
      kube-controller-manager-minikube   1/1     Running   1          175m
      kube-proxy-fsbvx                   1/1     Running   0          175m
      kube-scheduler-minikube            1/1     Running   1          175m
      storage-provisioner                1/1     Running   0          175m

    • Delete the CoreDNS pods with the following command:

      kubectl delete  pods coredns-66bff467f8-l6dzl coredns-66bff467f8-r78th  --namespace kube-system

      pod "coredns-66bff467f8-l6dzl" deleted
      pod "coredns-66bff467f8-r78th" deleted

  4. Now let's import the minikube-managed cluster to the hub cluster. For more information, see the product documentation.

    After import is complete, a list of running pods are dispalyed. Your results might resemble the following content:

    open-cluster-management-agent-addon   klusterlet-addon-appmgr-5794cb5589-92fpt                     1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-certpolicyctrl-786fd7fbdd-rz775             1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-iampolicyctrl-56f6cbb6d7-j26zc              1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-operator-76cfc678-6pj9t                     1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-policyctrl-config-policy-57b6f64f4d-tv9k7   1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-policyctrl-framework-6c9bcdfb44-4qv7f       3/3     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-search-85869f6775-6d6vp                     1/1     Running     0          1m
    open-cluster-management-agent-addon   klusterlet-addon-workmgr-79868b5fc4-692ps                    1/1     Running     0          1m
    open-cluster-management-agent         klusterlet-5f979dcc67-5k94t                                  1/1     Running     0          9m
    open-cluster-management-agent         klusterlet-registration-agent-68b54549f6-dsvmb               1/1     Running     0          8m
    open-cluster-management-agent         klusterlet-registration-agent-68b54549f6-gn49j               1/1     Running     0          8m
    open-cluster-management-agent         klusterlet-registration-agent-68b54549f6-z9tvd               1/1     Running     0          8m
    open-cluster-management-agent         klusterlet-work-agent-8454d74649-c9bp4                       1/1     Running     2          8m
    open-cluster-management-agent         klusterlet-work-agent-8454d74649-cbpbj                       1/1     Running     2          8m
    open-cluster-management-agent         klusterlet-work-agent-8454d74649-vf8zg                       1/1     Running     2          8m

Add a minishift-managed cluster

Add a Minishift cluster to help run OpenShift 3.11 cluster locally. For more information, see OKD Minishift. Complete the following steps to add a minishift-managed to the hub cluster:

  1. Install Minishift by running the following commands:

    # this step was necessary else minishift fails to start as the kvm-driver cannot be loaded
    curl -L https://github.com/dhiltgen/docker-machine-kvm/releases/download/v0.10.0/docker-machine-driver-kvm-centos7 >/tmp/docker-machine-driver-kvm
    chmod +x /tmp/docker-machine-driver-kvm
    sudo cp /tmp/docker-machine-driver-kvm /usr/local/bin/docker-machine-driver-kvm

    wget https://github.com/minishift/minishift/releases/download/v1.34.0/minishift-1.34.0-linux-amd64.tgz
    tar xzf minishift-1.34.0-linux-amd64.tgz
    sudo cp minishift-1.34.0-linux-amd64/minishift /usr/local/bin
    sudo chmod +x /usr/local/bin/minishift

    # it is important to set the OpenShift 3.11 Client when interacting with the 3.11 Minishift-Cluster
    eval $(minishift oc-env)

    minishift start
    oc config use-context minishift
    # login with a user who has admin-permissions
    oc login -u system:admin

  2. Add an entry into the hosts file to make the name resolution work. Run the following command:

minishift ssh
sudo echo '192.168.130.11 api.crc.testing' | sudo tee -a /etc/hosts

Because minishift is adding a new interface, you must add it to the firewall. Run the following commands:

sudo firewall-cmd --permanent --zone=trusted --add-interface=virbr2
sudo firewall-cmd --reload

# this step was also sometimes necessary
sudo service libvirtd restart
  1. Import the minishift-managed cluster to the hub cluster, similar to how Minikube was imported. For more information, see the product documentation.

Summary

In conclusion, we achieved the following task in this blog:

  • Installed Red Hat OpenShift Container Platfrom 4.5.7 with Red Hat Advanced Cluster Management for version 2.0.2.
  • Imported the following managed clusters to Red Hat Advanced Cluster Management:
    • Minikube with Kubernetes 1.18.3
    • Minishift with OpenShift 3.11.0 and Kubernetes 1.11.0

View the following screenshot to see an example of where the managed cluster information can be accessed on Red Hat Advanced Cluster Management for Kubernetes:

FinalACMCRC

It would be great to get feedback about this example and how to improve it. For example, this demonstration can be enhanced with other test-clusters like Kind. To learn more about Red Hat Advanced Cluster Management, see the product page.

저자 소개

Christian Stark

Christian Stark

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