Chapter 3. Preparing your hosts

1. Generate an SSH key on the host you run the installation playbook on:

   # ssh-keygen

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   Do not use a password.

2. Distribute the key to the other cluster hosts. You can use a bash loop:

   # for host in master.example.com \ 

   1

   
       node1.example.com \  

   2

   
       node2.example.com; \ 

   3

   
       do ssh-copy-id -i ~/.ssh/id_rsa.pub $host; \
       done

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   1 2 3

   Provide the host name for each cluster host.

3. Confirm that you can access each host that is listed in the loop through SSH.

1. On each host, register with RHSM:

   # subscription-manager register --username=<user_name> --password=<password>

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2. Pull the latest subscription data from RHSM:

   # subscription-manager refresh

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3. List the available subscriptions:

   # subscription-manager list --available --matches '*OpenShift*'

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4. In the output for the previous command, find the pool ID for an OpenShift Container Platform subscription and attach it:

   # subscription-manager attach --pool=<pool_id>

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5. Disable all yum repositories:

   1. Disable all the enabled RHSM repositories:

      # subscription-manager repos --disable="*"

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   2. List the remaining yum repositories and note their names under repo id, if any:

      # yum repolist

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   3. Use yum-config-manager to disable the remaining yum repositories:

      # yum-config-manager --disable <repo_id>

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      Alternatively, disable all repositories:

       yum-config-manager --disable \*

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      Note that this might take a few minutes if you have a large number of available repositories

6. Enable only the repositories required by OpenShift Container Platform 3.11.

   • For cloud installations and on-premise installations on x86_64 servers, run the following command:

     # 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-2.9-rpms"

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   • For on-premise installations on IBM POWER8 servers, run the following command:

     # subscription-manager repos \
         --enable="rhel-7-for-power-le-rpms" \
         --enable="rhel-7-for-power-le-extras-rpms" \
         --enable="rhel-7-for-power-le-optional-rpms" \
         --enable="rhel-7-server-ansible-2.9-for-power-le-rpms" \
         --enable="rhel-7-server-for-power-le-rhscl-rpms" \
         --enable="rhel-7-for-power-le-ose-3.11-rpms"

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   • For on-premise installations on IBM POWER9 servers, run the following command:

     # subscription-manager repos \
         --enable="rhel-7-for-power-9-rpms" \
         --enable="rhel-7-for-power-9-extras-rpms" \
         --enable="rhel-7-for-power-9-optional-rpms" \
         --enable="rhel-7-server-ansible-2.9-for-power-9-rpms" \
         --enable="rhel-7-server-for-power-9-rhscl-rpms" \
         --enable="rhel-7-for-power-9-ose-3.11-rpms"

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   Note

   Older versions of OpenShift Container Platform 3.11 supported only Ansible 2.6. The most recent versions of the playbooks now support Ansible 2.9, which is the preferred version to use.

For RHEL 7 systems:

1. Install the following base packages:

   # yum install wget git net-tools bind-utils yum-utils iptables-services bridge-utils bash-completion kexec-tools sos psacct

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2. Update the system to the latest packages:

   # yum update
   # reboot

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3. Install packages that are required for your installation method:

   • If you plan to use the containerized installer, install the following package:

     # yum install atomic

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   • If you plan to use the RPM-based installer, install the following package:

     # yum install openshift-ansible

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     Note

     If you encounter an error while running the yum install openshift-ansible command, see the resolution to fix that error.

     This package provides installer utilities and pulls in other packages that the cluster installation process needs, such as Ansible, playbooks, and related configuration files

For RHEL Atomic Host 7 systems:

1. Ensure the host is up to date by upgrading to the latest Atomic tree if one is available:

   # atomic host upgrade

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2. After the upgrade is completed and prepared for the next boot, reboot the host:

   # reboot

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For RHEL 7 systems:

1. Install Docker 1.13:

   # yum install docker-1.13.1

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2. Verify that version 1.13 was installed:

   # rpm -V docker-1.13.1
   # docker version

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