Init container
Ondat has requirements for the configuration of host systems. As such, Ondat starts an init container that sets the system configuration for Ondat. The container also manages configuration changes required when upgrading Ondat versions.
The container belongs to the DaemonSet that the Ondat Cluster
Operator starts when a
StorageOSCluster resource is created. The storageos-init container is
executed as an
initContainer
as part of a Kubernetes Pod. Therefore, only successful execution of the
storageos-init container processes will result in the main container
starting.
Script Framework
The code responsible for fulfilling the requirements is based on a Script Framework.
The script framework executes a set of scripts, performing checks, verifications and other procedures needed for Ondat to be able to start. The scripts stdout and stderr are written to the stdout and stderr of the init app. The container logs contain all the logs of the individual scripts that run. The exit statuses of the scripts are used to determine initialization failure or success. Any non-zero exit status is logged as an event in the Kubernetes Pod events.
If any of the scripts fail, the storageos-init container will propagate the
failure to Kubernetes, showing the status of the Pod as Init:Err.
To view the output of all storageos-init containers the following command can
be used:
kubectl -n kube-system logs -l app=storageos,kind=daemonset -c storageos-init
For more details, check the Ondat init container project.
Scripts executed
The storageos-init container executes the following scripts.