Configuring a node after install

c3os configuration mechanism is all based on cloud-config file.

By default, c3os reads in lexicographic order YAML cloud-config files in the /usr/local/cloud-config and /oem directories.

For instance, you should be able to see the configuration generated by the interactive-installer in the /oem/99_custom.yaml config file.

This mechanism can be used to set and enable persistent configuration on boot.

Examples

Below you will find some examples on how to use the cloud-config mechanism to enable/disable specific features.

Enabling ZRAM on boot

Copy the following file in /oem/100_zram.yaml or /usr/local/cloud-config/100_zram.yaml:

stages:
  boot:
       -  name: "zram setup"
          commands: 
          - modprobe zram
          - echo lzo > /sys/block/zram0/comp_algorithm
          - echo 1G > /sys/block/zram0/disksize
          - mkswap --label zram0 /dev/zram0
          - swapon --priority 100 /dev/zram0
name: "zfs setup"

This YAML will run the commands on boot enabling zram as swap.