Run rollover cronjob by default daily at midnight

[pavolloffay]

https://issues.jboss.org/browse/TRACING-824

The currently the default rollover configuration creates:

NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE
cronjob.batch/simple-prod-es-index-cleaner 55 23 * * * False 0 <none> 2m15s
cronjob.batch/simple-prod-es-lookback */30 * * * * False 0 <none> 2m15s
cronjob.batch/simple-prod-es-rollover */30 * * * * False 0 <none> 2m15s

The rollover condition: '{"max_age": "7d"}'

This means we run rollover cronjob every 30 minutes and the action takes place every week. Multiple runs a day make might make sense if the conditions are based on the size of the index - however this is supported only in ES6.

We should change the schedule to run once a day. I think it makes the most sense at the moment.

Regarding the default conditions - rollover every 7 days might be too much given the default (no rollover) strategy creates an index every day and some organizations keep the data only for 7 days. We should shrink it to 2 days by default - and raise discussion on the PR.

Signed-off-by: Pavol Loffay [email protected]

[jpkrohling]

Any reason not to use @daily? It's typically better to use this kind of notation, as it allows the scheduler to spread jobs across the day, to avoid all jobs to run at the same time.

[pavolloffay]

I wanted to pick the lowest traffic time rather than run it at random time.

[jpkrohling]

Do you mean that Kubernetes will run the same job at random times when @daily is set? That's certainly not in line with other cron implementations...

[pavolloffay]

Well didn't you just say it?

as it allows the scheduler to spread jobs across the day, to avoid all jobs to run at the same time.

I don't know how it is implemented. But I think it's better to run the rollover in low traffic hours.

[jpkrohling]

No, what I said is that the scheduler can spread the jobs (not executions) across the day. This way, your job might run every day at 4:07am (give or take).

[jpkrohling]

low traffic hours.

3am for some might be prime time for others :-)

[pavolloffay]

I see thanks for the explanation. Once the time set it will stick with that.

[objectiser]

As these are default values, I would recommend setting to midnight, as this is a natural day boundary. Then if users want something else, they will need to specify.

[jpkrohling]

For the record, @daily is still my preference, but LGTM.

[jpkrohling]

Should this be merged for 1.16, or post-1.16?