AWS c5.class unsupported?

[Rafal Lukawiecki]

> On 8 Nov 2017, at 00:47, Colin Percival <cperciva at tarsnap.com> wrote:
> 
> Actually no -- the problem I'm aware of has nothing to do with user-data
> scripts and should not affect instance launching.  I wouldn't be surprised
> if some instance launches are failing due to capacity issues though -- EC2
> often has such problems when they launch a new instance family.
> 
> The problem I'm tracking with C5 relates to disk hotplug: If you add an EBS
> volume, FreeBSD will not notice it until you run 'devctl rescan pci0', and
> if you remove an EBS volume FreeBSD will panic.  Warner is working on fixing
> the "hotunplug" path in the nvme driver in order to correct the panic; we
> were hoping to have it fixed in HEAD before C5 was launched, but I thought
> we had a few weeks left.
> 
> If you have a good test case for user-data script problems, please let me
> know (off-list).  Given how much new hardware and software there is in the C5
> instances I wouldn't be surprised if there are a few bugs lurking, and I'm
> sure my contacts at EC2 will be happy to receive reports.
> 
> (FWIW, C5 not being available in the Marketplace images is probably just a
> case of the Marketplace taking a while to get up to speed; I marked those
> images as "make these available on all new instances".  But I'll probably go
> in and disable C5 for now due to the disk attach/detach issues.)
> 
> -- 
> Colin Percival
> Security Officer Emeritus, FreeBSD | The power to serve
> Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid

It was odd. Your cloudconfig seemed not to run *some* of the scripts (or *none* of the scripts) that it got from the tar instance user-data. It could have been related to a fluke co-incidence. During the project development, I have, so far, launched 150+ t2.medium and c4.large and I have never had this issue. Today I thought of testing c5.large but I have only launched 12 of them. I had this problem in 1 case out of the 12.

On a side note, the performance our optimised web heads running FreeBSD 11.1 + PHP 7 + Drupal 7 got from c5.large was on-par or a little worse than from t2.medium in a short but intensive load test. I was surprised, so perhaps there are some other issues lurking beneath. I was also hoping the slowish EFS access would be faster, but it is no different at the low-end of EFS storage it seems. Of course, t2 is limited to bursts, so this is not a fair comparison to c5, but I was still hoping to see better results even in a 5 min load.

More testing needed, results inconclusive, I suppose. I am on a deadline to complete the project this week, so I won’t go back to c5 testing but happy to do that in about 5 weeks from now.

Rafal