The kURL installer runs host preflight checks to detect problems with the target environment early in the installation process. A variety of different types of host preflights can be run to check for various conditions. These checks can also run conditionally, depending on whether the installer is performing an upgrade or a join, whether it's an air gap installation, and so on.
The installer has default host preflight checks that run to ensure that certain conditions are met (such as supported operating systems, disk usage, and so on). The default host preflight checks are designed and maintained to help ensure the successful installation and ongoing health of the cluster. The default preflight checks are also customizable. New host preflight checks can be added to run in addition to the defaults, or the default checks can be disabled to allow for a new set of host preflight checks to run instead. For more information, see customizing host preflight checks.
Host prelight failures block the installation from continuing and exit with a non-zero return code. This behavior can be changed as follows:
host-preflight-enforce-warnings flag can be used to block the installation on warnings.
exclude-builtin-host-preflights flag can be used to skip the default host preflight checks and run only the custom checks.
The following sections detail the default host preflight checks.
The following checks run on all nodes during installations and upgrades:
The following checks run on all nodes during installations only:
These checks run only on primary nodes during new installations:
These checks run on all primary and secondary nodes joining an existing cluster:
Some checks only run when certain add-ons are enabled or configured in a certain way in the installer:
These checks only run on installations with Flannel:
These checks only run on installations with Weave:
These checks only run on installations with Rook:
This check only runs on installations with OpenEBS when cStor is enabled:
This check only runs on installs with Prometheus:
This check only runs on installations with Longhorn:
These checks only run on installations with Docker:
This check runs on installations and upgrades with Containerd:
This check runs on online (not air gap) installations and upgrades with KOTS: