How To Add a Monitored Service

Agenda

Monitor Stack
Add Monitor Stack
Verification

This HowTo describes how to add the monitor stack to your software release in the context of html5as-base software release.

Here is the commit introducing this functionality to html5as software release: commit diff.

Add Monitored Services

Monitored Services are run by supervisord.
Any executable placed in INSTANCE-ROOT/etc/service/ will automatically be considered a monitored service.
To add a monitored service to an instance, render its executable in INSTANCE-ROOT/etc/service/

Services that are not running will be started automatically at the end of an instanciation.

If a monitored Service exit, the signal will trigger an alert to the local SlapOS master forcing the reprocessing of the instance and all its dependecies in order to get back to an expected state. The -on-watch postfix is added to the service name in supervisord in order to mark this service as monitored.

Monitor Web Service

Change the executable launcher from ${basedirectory:script} to ${basedirectory:service}

[html5as]
...
# Executables
bin_launcher = ${basedirectory:service}/launcher

Update md5sum

Refer How To Move to md5sum automatic update to update md5sum:

$ cd ~/srv/project/slapos/software/html5as-base
$ ../../update-hash

Validation

Verify Launcher renamed

Verify Launcher renamed

The instance should be re-instantiated:

$ slapos node instance --all

You can get the status of services run by supervisord via

& slapos node status

Launcher is now named to launcher-on-watch.