Fix "Connection closed by remote host" error on Google Cloud ssh

[teor2345]

Motivation

A few different PRs seem to be failing with this error:

kex_exchange_identification: Connection closed by remote host
https://github.com/ZcashFoundation/zebra/runs/8161163434?check_suite_focus=true#step:7:86

[teor2345]

I haven't seen these errors recently, I wonder if they are caused by rate-limiting?

We could add the ConnectionAttempts option to the SSH command-line to fix this.

[teor2345]

This happened again today:
https://github.com/ZcashFoundation/zebra/actions/runs/3033472434/jobs/4881881486#step:8:106

[teor2345]

Failed on main:
https://github.com/ZcashFoundation/zebra/actions/runs/3053855581/jobs/4926083103#step:6:105

[teor2345]

It looks like this is now more frequent than the other Google Cloud errors.

[teor2345]

Failed 3 times on main in the same workflow:
https://github.com/ZcashFoundation/zebra/actions/runs/3150972503/jobs/5131855566
https://github.com/ZcashFoundation/zebra/actions/runs/3150972503/jobs/5131861932
https://github.com/ZcashFoundation/zebra/actions/runs/3150972503/jobs/5131846881

[gustavovalverde]

The main branch has been failing recently with this errors. So I'm reopening this one

[gustavovalverde]

I've been able to find this error log in GCP

Supplied fingerprint does not match current metadata fingerprint.

I've also found the root cause: some ssh-keys in the project metadata that might have been added when testing OS Login.

This might not solve the problem, but will at least reduce the noise when searching for the actual error.

[teor2345]

I've also found the root cause: some ssh-keys in the project metadata that might have been added when testing OS Login.

Thanks for tracking this down!