Allow no more than 100 instances to be created on each resizing run

Allow no more than 100 instances to be created on each resizing run

Together with the cron configuration for the resize job, this will limit the rate at which instances are created.

BUG=620534
Committed: https://github.com/luci/luci-py/commit/1487682e535e2425d22a6d7fd9997b7826474430

[smut, 2016-06-29 23:13:59]

smut@google.com changed reviewers:
+ vadimsh@chromium.org

[smut, 2016-06-29 23:13:59]

Cron timing is still 1 minute so this will enforce a maximum of 100 VMs booting
up per minute. Should be okay since we were at 100 for awhile and you only
noticed a problem when we tried 400, but we can adjust this later.

[Vadim Sh., 2016-06-29 23:17:48]

https://codereview.chromium.org/2110253003/diff/1/appengine/gce-backend/insta...
File appengine/gce-backend/instance_group_managers.py (right):

https://codereview.chromium.org/2110253003/diff/1/appengine/gce-backend/insta...
appengine/gce-backend/instance_group_managers.py:316: if response['targetSize']
>= target_size:
how is it going to scale down then if we change minimum_size?

[smut, 2016-06-29 23:24:38]

https://codereview.chromium.org/2110253003/diff/1/appengine/gce-backend/insta...
File appengine/gce-backend/instance_group_managers.py (right):

https://codereview.chromium.org/2110253003/diff/1/appengine/gce-backend/insta...
appengine/gce-backend/instance_group_managers.py:316: if response['targetSize']
>= target_size:
On 2016/06/29 23:17:48, Vadim Sh. wrote:
> how is it going to scale down then if we change minimum_size?

We never scale down, we just wait for excess VMs to drain away.

So for example if target size is 10 and then we change target size to 5 then we
will stay at 10 until 5 VM leases expire and we delete them. Deleting a VM from
an instance group decreases size, so we will eventually come down to 5.

[Vadim Sh., 2016-06-29 23:31:11]

lgtm

[smut, 2016-06-29 23:32:11]

The CQ bit was checked by smut@google.com

[commit-bot: I haz the power, 2016-06-29 23:32:14]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-29 23:33:51]

Description was changed from

==========
Allow no more than 100 instances to be created on each resizing run

Together with the cron configuration for the resize job, this will limit the
rate at which instances are created.

BUG=620534
==========

to

==========
Allow no more than 100 instances to be created on each resizing run

Together with the cron configuration for the resize job, this will limit the
rate at which instances are created.

BUG=620534

Committed:
https://github.com/luci/luci-py/commit/1487682e535e2425d22a6d7fd9997b7826474430
==========

[commit-bot: I haz the power, 2016-06-29 23:33:52]

Committed patchset #1 (id:1) as
https://github.com/luci/luci-py/commit/1487682e535e2425d22a6d7fd9997b7826474430