williamcaban/openshift-lab

OpenShift inventory file for POCs or lab environments

ABOUT THIS REPO

This repository is a prescriptive OpenShift inventory file I for my lab environment and some notes on the installation process. The inventory file is verbose to allow for quick adjustment during tests.

To customize the inventory file to your environment you may reference the official OpenShift documentation:

https://docs.openshift.com/container-platform/3.11/install/configuring_inventory_file.html

LAB CONCEPTUAL DIAGRAM

• The [LB] represents a dedicated RHEL minimal server OpenShift can configure to serve as the load balancer for the Master Nodes. In a production environment this may be replaced by load balancer configured in passthrough mode.

ENVIRONMENT REQUIREMENTS

1. Ensure DNS resolution of all nodes FQDN
2. Register the FQDN for the cluster consoles like ocp-console.example.com (openshift_master_cluster_hostname)
3. Register the wildcard subdomain for the apps like *.apps.example.com (openshift_master_default_subdomain)
4. Ensure SELinux in enforcing mode

HOST PREPARATION

NOTE 1: This is only a summary. For detailed information visit: https://docs.openshift.com/container-platform/latest/install/host_preparation.html

NOTE 2: The following instructions assume the use of a bastion node to deploy OpenShift

1. Ensure bastion node has ssh access to all nodes

$ ssh-keygen

$ for host in master1.example.com \
master2.example.com \
master3.example.com \
infranode1.example.com \
infranode2.example.com \
node1.example.com \
node4.example.com \
node3.example.com \
ocs-node1.example.com \
ocs-node2.example.com \
ocs-node3.example.com; \
do ssh-copy-id -i ~/.ssh/id_rsa.pub $host; \
done

2. Register the host

# register each host with RHSM
subscription-manager register --username=<user_name> --password=<password>

# pull subscriptions
subscription-manager refresh

# identify the available OpenShift subscriptions
subscription-manager list --available --matches '*OpenShift*'

# assign a subscription to the node
subscription-manager attach --pool=<pool_id>

3. Assign subscription to the host

# Disable all RHSM repositories
subscription-manager repos --disable="*"

# Enable only repositories required by OpenShift
subscription-manager repos \
    --enable="rhel-7-server-rpms" \
    --enable="rhel-7-server-extras-rpms" \
    --enable="rhel-7-server-ose-3.11-rpms" \
    --enable="rhel-7-server-ansible-2.6-rpms"

4. Make sure the systems have the latest patches

# Update RHEL
yum -y update

# Reboot with updated Kernel
reboot

INSTALLING OPENSHIFT

1. Install required installation tools at bastion node

$ yum -y install atomic-openshift-clients openshift-ansible

2. Prepare your custom inventory file. (See reference template in this repo)

3. Copy your OpenShift Ansible inventory file to the bastion node. Either using the bastion Ansible host file or maintaining a local inventory_file

/etc/ansible/hosts

_or_

~/inventory_file

• Inventory configuration details: https://docs.openshift.com/container-platform/3.11/install/configuring_inventory_file.html

4. Validate bastion can reach all the nodes

ansible all -i inventory_file -m ping

5. From bastion node run the installation of prerequisites (base packages & Docker) on all OpenShift nodes

ansible-playbook -f 20 -i inventory_file /usr/share/ansible/openshift-ansible/playbooks/prerequisites.yml

NOTE: In case of error indicating playbooks are not found, install the corresponding package in the bastion node executing: yum install openshift-ansible

NOTE: The -i <inventory_file> flag is not needed if using the default inventory path /etc/ansible/hosts

6. Once the previous step is completed WITHOUT any error, you may proceed with the deployment.

   Deploy OpenShift using the ansilbe-playbook

ansible-playbook -f 20 -i inventory_file /usr/share/ansible/openshift-ansible/playbooks/deploy_cluster.yml

NOTE: If the initial installation fails you need to uninstall OpenShift and start the installation from the prerequisites playbook.

UNINSTALLING OPENSHIFT

# Uninstall OpenShift
ansible-playbook -i inventory_file /usr/share/ansible/openshift-ansible/playbooks/adhoc/uninstall.yml

# Remove leftover configs and certs from master and nodes
ansible nodes -i inventory_file -m file -a "dest=/etc/origin state=absent"
ansible nodes -i inventory_file -m file -a "dest=/etc/cni state=absent"

(optional) Reset iptables config after CNI failed installations

Under certain installation failure scenarios (specially with network plugins) there might be some iptables entries left behind. To reset these you should have a clean iptables backup.

NOTE: The following is a sample iptables.plain from VMs running in a RHV environment:

# filename: iptables.plain
# sample configuration for iptables service
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p udp -m multiport --dports 60001:60005 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

To restore this iptables config to all the nodes use:

ansible nodes -i inventory_file -m copy -a "src=./iptables.plain dest=/etc/sysconfig/iptables"

Restart iptables service. Some CNI plugin installation failures might require a reboot of the node.

UNINSTALLING RHOCS

# Uninstall OCS
ansible-playbook -i <path_to_inventory_file> /usr/share/ansible/openshift-ansible/playbooks/openshift-glusterfs/uninstall.yml

# Uninstall OCS deleting data
ansible-playbook -i <path_to_inventory_file> -e "openshift_storage_glusterfs_wipe=true" /usr/share/ansible/openshift-ansible/playbooks/openshift-glusterfs/uninstall.yml

# Cleaning OCS leftovers
ansible -i inventory_file glusterfs -a "rm -rf /var/lib/heketi /etc/glusterfs  /var/lib/glusterd /var/log/glusterfs"

# Clean partitions of OCS target disks
ansible -i inventory_file glusterfs -a "wipefs -a -f /dev/<path_to_disks>"

TESTING THE OPENSHIFT INSTALLATION

Setting up bastion node for system:admin access

To use the bastion node for cluster administration, copy the .kube directory from master1 to your bastion

ansible -i inventory_file masters[0] -b -m fetch -a "src=/root/.kube/config dest=/root/.kube/config flat=yes"

Once the .kube directory is in your bastion node, validate you are system:admin

oc whoami

Verifying the environment

The following commands you be successful

oc get nodes --show-labels

oc get nodes -o wide

oc get pod --all-namespaces -o wide

oc login -u <ocp_user>

Login into the web console by accessing the name indicated in the openshift_master_cluster_hostname variable of the inventory_file (i.e. https://openshift-console.example.com)

Try some demo applications to test the environment.

I have some simple demo activities here: https://github.com/williamcaban/podcool-docs

Custom Certificates

Deploying custom certificates are not part of this lab documentation. If need to use custom certificates refer to the following documentation

• Configuring Custom Certificates

  https://docs.openshift.com/container-platform/3.11/install_config/certificate_customization.html

• Redeploying Certificates

  https://docs.openshift.com/container-platform/3.11/install_config/redeploying_certificates.html

• To deploy OpenShift named certificates

  https://gist.github.com/abutcher/2e13e963a6c241cc5e90

openshift-lab's Issues

assume NFS server configure to export /srv/nfs

hi, can you explain what you mean by NFS server configure to export /srv/nfs ?
do I need to install a local nfs_server locally or just a nfs_client that point to a remote nfs_server exporting /srv/nfs ?
thanks