Hello admins of EU AWS systems – DNS outage in eu-west-1

[danielhunt]

https://status.aws.amazon.com

Looks like there's a DNS outage in AWS Dublin

All DNS request coming from `eu-west-1b` fail completely if you're using the default AWS DNS resolution itself - if you switch to `8.8.8.8` it's all totally fine, but that's of no use if you have private services that need internal AWS resolution

`1a` and `1c` are also affected, but to a much lower extent from what I can tell

[aidos]

Question for the more experienced in the group - is there a way of caching the DNS locally within you VPC in case something like this happens again? Or does that just cause more issues than it solves?

When I discovered it I tried switching my resolv.conf to 8.8.8.8 but of course none of my internal stuff worked because of how my security group / subnet / ip restrictions are setup internally.

[jlgaddis]

I'm not a big user of AWS but I don't know that there's anything stopping you from running your own recursive resolver (in your VPC) that your other machines use (instead of using an external resolver or whatever Amazon provides).

You could, for instance, stand up an instance or two running Unbound, forward to Amazon's own resolvers for internal stuff, and forward to external resolvers for external resolution (or just handle it yourself instead of using forwarders).

[chatmasta]

Yes, you can specify DNS server to use in the DHCP options set of the VPC. I've done this to point to internal DNS servers.

[fern4lvarez]

It's weird, I see actually most of my issues coming from instances located in `eu-west-1a`, whereas `eu-west-1b` and `eu-west-1c` look fine.

[aidos]

I recall reading somewhere many years ago that AWS randomise a, b, c etc per account. Otherwise people have a tendency to pick A and be done with it.

[danielhunt]

Interesting difference in experience there

Complicated networks are complicated, I suppose

[danielhunt]

Seeing an increase in errors in `1a` and `1c` now myself too

[neo2001]

6:29 PM PST We have identified the root cause of the DNS resolution issues in the EU-WEST-1 Region and continue working towards resolution.

[paugay]

same here :) let's see how long it takes

[neo2001]

sigh