Batch jobs scheduled multiple times when node goes down, regardless if drained or just stopped

[g0t4]

Nomad version

Nomad v0.3.1

Operating system and Environment details

centos 7 3.10.0-327.10.1.el7.x86_64
Docker version 1.10.3, build 20f81dd

Issue

I have batch jobs with 50 tasks. If i take a node down while it is processing work and then bring a new node up, the work from the node that went down tends to be run multiple times, like up to 50 times, seemingly endlessly. I have to stop the job to get it to stop scheduling new allocations, even as the previous runs complete successfully, that doesn't stop Nomad from continuing to schedule new allocations.

I ran into this issue both by just shutting down a node, and by draining a node. So this seems like an issue in either case.

Is something going wrong with evaluations if a node goes down?

Shouldn't we be able to lose a node and have the processing eventually move to another machine?

I don't have count set on the tasks, so I don't know why nomad would run multiple occurrences.

Reproduction steps

Launch a batch job with work running on multiple nodes. Take one node down, bring up a new node in its place. Might not need to bring up a new node, that's just something auto scaling is doing in my situation.

[g0t4]

A small discussion was already had here https://groups.google.com/forum/#!searchin/nomad-tool/multiple/nomad-tool/97IHLdr4FX8/c1ujs8DXBgAJ

[dadgar]

@g0t4 Could you please share the Nomad server logs of this happening and the job file. How many clients do you have running?

I was not able to reproduce using the instructions. I used two clients running a docker container in batch mode, killing one of the clients.

[g0t4]

I was able to reproduce with a generic batch job composed of sleeps, attached is the job file
repro.hcl.txt

Here's a video explaining the steps to reproduce: https://youtu.be/Pm0nQtqQlWk

Hope this helps, let me know if you want anything else. The video includes a dump of the server logs in that example if you want to see those without trying the repro on your end.

[dadgar]

@g0t4 just watched the video. That does look like a nasty bug! I will pull down that file tomorrow and try to do the repro. I think one of the differences when I was trying to reproduce it earlier today was that I had a task group with one task and had the count set to ~20, whereas you have each task separately defined.

[g0t4]

Glad the video helped! I figured that was easier to explain what was going
on :)

Let me know if I can help with anything else, I'd be happy to test things
when you have updates.

On Mon, Apr 11, 2016 at 9:10 PM, Alex Dadgar [email protected]
wrote:

@g0t4 https://github.com/g0t4 just watched the video. That does look
like a nasty bug! I will pull down that file tomorrow and try to do the
repro. I think one of the differences when I was trying to reproduce it
earlier today was that I had a task group with one task and had the count
set to ~20, whereas you have each task separately defined.

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[dadgar]

Hey Wes,

Do you want to try this branch and make sure the fix works:
#1086

Thanks,
Alex

On Mon, Apr 11, 2016 at 6:52 PM, Wes Higbee [email protected]
wrote:

Glad the video helped! I figured that was easier to explain what was going
on :)

Let me know if I can help with anything else, I'd be happy to test things
when you have updates.

On Mon, Apr 11, 2016 at 9:10 PM, Alex Dadgar [email protected]
wrote:

@g0t4 https://github.com/g0t4 just watched the video. That does look
like a nasty bug! I will pull down that file tomorrow and try to do the
repro. I think one of the differences when I was trying to reproduce it
earlier today was that I had a task group with one task and had the count
set to ~20, whereas you have each task separately defined.

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Reply to this email directly or view it on GitHub
#1050 (comment)

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#1050 (comment)

[g0t4]

Will do, thanks!

On Tue, Apr 12, 2016 at 7:16 PM, Alex Dadgar [email protected]
wrote:

Hey Wes,

Do you want to try this branch and make sure the fix works:
#1086

Thanks,
Alex

On Mon, Apr 11, 2016 at 6:52 PM, Wes Higbee [email protected]
wrote:

Glad the video helped! I figured that was easier to explain what was
going
on :)

Let me know if I can help with anything else, I'd be happy to test things
when you have updates.

On Mon, Apr 11, 2016 at 9:10 PM, Alex Dadgar [email protected]
wrote:

@g0t4 https://github.com/g0t4 just watched the video. That does look
like a nasty bug! I will pull down that file tomorrow and try to do the
repro. I think one of the differences when I was trying to reproduce it
earlier today was that I had a task group with one task and had the
count
set to ~20, whereas you have each task separately defined.

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You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
<#1050 (comment)

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#1050 (comment)

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#1050 (comment)

[g0t4]

Works with my mock job file that I sent you, if I get a chance this week
I'll try to swap this into my test cluster and put real work against it.
How stable is this branch?

On Tue, Apr 12, 2016 at 8:40 PM, Wes Higbee [email protected] wrote:

Will do, thanks!

On Tue, Apr 12, 2016 at 7:16 PM, Alex Dadgar [email protected]
wrote:

Hey Wes,

Do you want to try this branch and make sure the fix works:
#1086

Thanks,
Alex

On Mon, Apr 11, 2016 at 6:52 PM, Wes Higbee [email protected]
wrote:

Glad the video helped! I figured that was easier to explain what was
going
on :)

Let me know if I can help with anything else, I'd be happy to test
things
when you have updates.

On Mon, Apr 11, 2016 at 9:10 PM, Alex Dadgar [email protected]
wrote:

@g0t4 https://github.com/g0t4 just watched the video. That does
look
like a nasty bug! I will pull down that file tomorrow and try to do
the
repro. I think one of the differences when I was trying to reproduce
it
earlier today was that I had a task group with one task and had the
count
set to ~20, whereas you have each task separately defined.

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https://github.com/hashicorp/nomad/issues/1050#issuecomment-208652525>

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#1050 (comment)

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[g0t4]

Thanks a bunch for fixing this so quickly!

On Tue, Apr 12, 2016 at 10:24 PM, Wes Higbee [email protected] wrote:

Works with my mock job file that I sent you, if I get a chance this week
I'll try to swap this into my test cluster and put real work against it.
How stable is this branch?

On Tue, Apr 12, 2016 at 8:40 PM, Wes Higbee [email protected] wrote:

Will do, thanks!

On Tue, Apr 12, 2016 at 7:16 PM, Alex Dadgar [email protected]
wrote:

Hey Wes,

Do you want to try this branch and make sure the fix works:
#1086

Thanks,
Alex

On Mon, Apr 11, 2016 at 6:52 PM, Wes Higbee [email protected]
wrote:

Glad the video helped! I figured that was easier to explain what was
going
on :)

Let me know if I can help with anything else, I'd be happy to test
things
when you have updates.

On Mon, Apr 11, 2016 at 9:10 PM, Alex Dadgar <[email protected]

wrote:

@g0t4 https://github.com/g0t4 just watched the video. That does
look
like a nasty bug! I will pull down that file tomorrow and try to do
the
repro. I think one of the differences when I was trying to reproduce
it
earlier today was that I had a task group with one task and had the
count
set to ~20, whereas you have each task separately defined.

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https://github.com/hashicorp/nomad/issues/1050#issuecomment-208652525>

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#1050 (comment)

[dadgar]

@g0t4 thanks for testing that! I would just wait for 0.3.2-RC which should be out soon!

[g0t4]

Fantastic, looking forward to it!

On Wed, Apr 13, 2016 at 12:42 PM, Alex Dadgar [email protected]
wrote:

@g0t4 https://github.com/g0t4 thanks for testing that! I would just
wait for 0.3.2-RC which should be out soon!

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