4.2 NTP Setup

Configuring a time source for the disconnected cluster

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If you set additionalNTPSources in your agent-config.yaml, skip this step, you do not need to do this as NTP would've been configured during install.

We need to apply a custom Network Time Protocol (NTP) configuration to the nodes, because by default, internet connectivity is assumed in OpenShift Container Platform and chronyd is configured to use the *.rhel.pool.ntp.org servers.

1. Create a Butane config including the contents of the chrony.conf file. For example, to configure chrony on master nodes, create a 99-master-chrony.bu file. Do the same for worker nodes by swapping the metadata name and the machineconfiguration.openshift.io/role label.

   The Butane version you specify in the config file should match the OpenShift Container Platform version and always ends in 0. For example, 4.17.0.

variant: openshift
version: 4.17.0
metadata:
  name: 99-master-chrony # (1)! On control plane nodes, substitute master for worker in both of these locations
  labels:
    machineconfiguration.openshift.io/role: master # (2)! On control plane nodes, substitute master for worker in both of these locations
storage:
  files:
  - path: /etc/chrony.conf
    mode: 0644 # (3)! Specify an octal value mode for the mode field in the machine config file
    overwrite: true
    contents:
      inline: | # (4)! Specify any valid, reachable time source. `172.16.10.123` is an example time server. IP address or hostname is accepatable 
        pool 172.16.10.123 iburst
        driftfile /var/lib/chrony/drift
        makestep 1.0 3
        rtcsync
        logdir /var/log/chrony

2. Use Butane to generate a MachineConfig object file, 99-master-chrony.yaml, containing the configuration to be delivered to the nodes

butane 99-master-chrony.bu -o 99-master-chrony.yaml

3. Apply the configurations in one of two ways:
• If the cluster is not running yet, after you generate manifest files, add the MachineConfig object file to the installation_directory/openshift directory, and then continue to create the cluster.
• If the cluster is already running, apply the file

oc apply -f ./99-master-chrony.yaml

1. On worker nodes, change master to worker
2. On worker nodes, change master to worker
3. Specify an octal value mode for the mode field in the machine config file. After creating the file and applying the changes, the mode is converted to a decimal value. You can check the YAML file with the command oc get mc <mc-name> -o yaml
4. Specify any valid, reachable time source. 172.16.10.123 is an example time server. IP address or hostname is accepatable