InstanceBootCommand
A single line of shell script to run (as root) as a cloud-init command early during instance boot.
For more information about using cloud-init with EC2, see the AWS doc Running Commands on Your Linux Instance at Launch. For cloud-init specifics, see "bootcmd" in the doc Run commands on first boot.
The InstanceBootCommand will also apply to any build instance associated with the Rack.
| Default value | "" |
Use Cases
- Setting kernel parameters such as
vm.max_map_countfor workloads like Elasticsearch - Configuring custom networking or DNS settings before the ECS agent starts
- Installing required kernel modules or drivers that must be loaded early in the boot process
Additional Information
Example: increase virtual memory
Tell the host EC2 instance to set operating system limits on mmap to 262144 (useful for Elasticsearch):
$ convox rack params set 'InstanceBootCommand="sysctl -w vm.max_map_count=262144"'
Updating parameters... OK
(Note the surrounding single quotes in the above command.)
The InstanceBootCommand runs during the bootcmd phase of cloud-init, which executes on every boot of the instance (not just the first boot). This makes it suitable for kernel tuning and other settings that need to persist across reboots.
See Also
