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https://issues.apache.org/jira/browse/AIRFLOW-6389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17045895#comment-17045895
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t oo commented on AIRFLOW-6389:
-------------------------------
t
https://jira.apache.org/jira/browse/AIRFLOW-6389 any suggestions on which .py
file to change to implement this? could jobs table help?
6 replies
ash 22 hours ago
That is more than a single file change
ash 22 hours ago
It's my next two months worth of work!
t 22 hours ago
I'm not saying support HA, just prevent 2nd scheduler pid starting
ash 21 hours ago
Oh to detect running pid that should be in the cli/commands/ folder
ash 21 hours ago
I don't think there's a need for a config option
ash 21 hours ago
If it's configured to write a pid, and that already exists and is a live
process it should refuse to run
> add config for 'allow_multi_scheduler_instances' default True
> -------------------------------------------------------------
>
> Key: AIRFLOW-6389
> URL: https://issues.apache.org/jira/browse/AIRFLOW-6389
> Project: Apache Airflow
> Issue Type: New Feature
> Components: scheduler
> Affects Versions: 1.10.6
> Reporter: t oo
> Priority: Minor
>
> right now common deployment pattern with blue/green build is:
> 1. on EC2 1, start scheduler
> 2. Assign 'final' DNS to EC2 1
> 3. create EC2 2
> 4. start scheduler on EC2 2
> 5. Assign 'final' DNS to EC2 2
> 6. Teardown EC2 1
> Issue is that since the metastore db (ie mysql) is shared to both EC2s there
> is a period of time between point 4 and 6 above where there are multiple
> schedulers running. To avoid this proposing config for
> 'allow_multi_scheduler_instances' that when set to False, the startup of
> scheduler will detect that another scheduler is running then exit (ie not
> startup) with WARNING message
> 7. We have cron/systemd setup to keep retrying to to start the scheduler pid,
> so as soon as point 6 completes scheduler should successfully launch on EC2 1
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