## Problem
#4598 compute nodes are not accessible some time after wake up due to
kubernetes DNS not being fully propagated.
## Summary of changes
Update connect retry mechanism to support handling IO errors and
sleeping for 100ms
## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
Make it possible to specify directory where proxy will look up for
extra certificates. Proxy will iterate through subdirs of that directory
and load `key.pem` and `cert.pem` files from each subdir. Certs directory
structure may look like that:
certs
|--example.com
| |--key.pem
| |--cert.pem
|--foo.bar
|--key.pem
|--cert.pem
Actual domain names are taken from certs and key, subdir names are
ignored.
This fixes all kinds of problems related to missing params,
like broken timestamps (due to `integer_datetimes`).
This solution is not ideal, but it will help. Meanwhile,
I'm going to dedicate some time to improving connection machinery.
Note that this **does not** fix problems with passing certain parameters
in a reverse direction, i.e. **from client to compute**. This is a
separate matter and will be dealt with in an upcoming PR.
This patch aims to fix some of the inconsistencies in error reporting,
for example "Internal error" or "Console request failed" instead of
"password authentication failed for user '<NAME>'".
