Run-once tasks

    You are viewing documentation for a release that is no longer supported. The latest supported version of version 3 is [3.11]. For the most recent version 4, see

    After installing OKD, your system might need extra configuration to ensure your hosts consistently run smoothly.

    While these are classified as run-once tasks, you can perform any of these at any time if any circumstances change.

    NTP (Network Time Protocol) is for keeping hosts in sync with the world clock. Time synchronization is important for time sensitive operations, such as log keeping and time stamps, and is highly recommended for Kubernetes, which OKD is built on. OKD operations include etcd leader election, health checks for pods and some other issues, and helps prevent time skew problems.

    Depending on your instance, NTP might not be enabled by default. To verify that a host is configured to use NTP:

    If both NTP enabled and NTP synchronized are yes, then NTP synchronization is active.

    To install the ntp package, run the following command:

    1. # timedatectl set-ntp true

    To install the chrony package, run the following commands:

    For more information about the timedatectl command, timezones, and clock configuration, see Configuring the date and time and .

    OKD uses entropy to generate random numbers for objects such as IDs or SSL traffic. These operations wait until there is enough entropy to complete the task. Without enough entropy, the kernel is not able to generate these random numbers with sufficient speed, which can lead to timeouts and the refusal of secure connections.

    To check available entropy:

    1. $ cat /proc/sys/kernel/random/entropy_avail

    The available entropy should be verified on all node hosts in the cluster. Ideally, this value should be above .

    Alternatively, you can use the rngtest command to check not only the available entropy, but if your system can feed enough entropy as well:

    The rngtest command is available from the rng-tools

    If the above takes around 30 seconds to complete, then there is not enough entropy available.

    Depending on your environment, entropy can be increased in multiple ways. For more information, see the following blog post: https://developers.redhat.com/blog/2017/10/05/entropy-rhel-based-cloud-instances/.

    Generally, you can increase entropy by installing the rng-tools package and enabling the rngd service:

    1. # yum install rng-tools

    Once the rngd service has started, entropy should increase to a sufficient level.

    For proper functionality of dynamically provisioned persistent storage, the default storage class needs to be defined. During the installation, this default storage class is defined for common cloud providers, such as Amazon Web Services (AWS), Google Cloud Platform (GCP), and more.

    The above output is taken from an OKD instance running on GCP, where two kinds of persistent storage are available: standard (HDD) and SSD. Notice the standard storage class is configured as the default. If there is no storage class defined, or none is set as a default, see the section for instructions on how to set up a storage class as suggested.