Config CLI

When the startscript gets executed for a lifecycle event it will usually need to retrieve metadata about the environment so that you can control how the script reacts to the event.

The Config CLI allows you to retrieve metadata.

/etc/guestconfig/configmeta.json

The metadata can be found in the pods in /etc/guestconfig/configmeta.json.

Exploring the Config CLI

I wasn't able to find documentation on the Config CLI so let's do some exploring.

Config CLI

The Config CLI is installed automatically in containers that have a config package.

If this exercise we use the Centos 7 KubeDirectorCluster running from the previous lesson that has a config package defined:

{
...
"defaultConfigPackage": {
"packageURL": "file:///opt/configscripts/appconfig.tgz"
},
...
}

You should still have your KubeDirectorCluster running from the previous lesson if not, start it now.

Next open a shell session on the cluster:

kubectl exec -it your-pod-name -- /bin/bash

Now execute the configcli application:

[root@kdss-xkdsh-0 /]# configcli
Configuration CLI 1.0.
ccli>

From here you can explore the help:

ccli> help
Documented commands (type help <topic>):
________________________________________
EOF baseimg ccli exit help macro namespace

And ...

ccli> help namespace
usage: namespace [-h]
{node,version,cluster,distros,services,tenant,auth,platform}
...
Access to all available configuration namespaces.
optional arguments:
-h, --help show this help message and exit
Subcommands:
{node,version,cluster,distros,services,tenant,auth,platform}
node The node namespace from the application configuration
metadata
version The version namespace from the application
configuration metadata
cluster The node namespace from the application configuration
metadata
distros The distros namespace from the application
configuration metadata.
services The services namespace from the application
configuration metadata.
tenant The tenant namespace from the application
configuration metadata.
auth The auth namespace from the application configuration
metadata.
platform The platform namespace from the application
configuration metadata.

You can then retrieve specific information:

ccli> namespace distros
bluedata/centos7x

When we are done we can exit:

ccli> exit
[root@kdss-xkdsh-0 /]#
info

If some of the configcli commands do not work as expected, it could be due to the following issue

Using from a shell script

From a shell appconfig script (e.g. startscript) you can call the configcli directly, e.g.

[root@kdss-xkdsh-0 /]# echo $(configcli namespace distros)
bluedata/centos7x

Using from a Python script

info

App config scripts (e.g. startscript) can also be written in Python.

Information on writing startscript in Python is an advanced topic and will be covered later.

Exercise

Update the startscript from the previous lesson to use the configcli in some way.

References

Edit this page