Host key verification failed - first run after Archer2 restart

1

Hi,

I’m trying to run u-cw305 but get the below error.

[FAIL] ssh -oBatchMode=yes -n jweber@login.archer2.ac.uk env\ ROSE_VERSION=2019.01.3\ CYLC_VERSION=7.8.12\ bash\ -l\ -c\ '"$0"\ "$@"'\ rose\ suite-run\ -vv\ -n\ u-cw305\ –run=run\ –remote=uuid=26640088-3813-4324-9221-885e032d8631,now-str=20230723T214333Z,root-dir='$DATADIR' # return-code=255, stderr=

[FAIL] Host key verification failed.

This is the first run I’ve tried since Archer2 came back on line - is there something I need to change on Puma?

Thanks,

James

2

Hi James,

This is the change of host key when ARCHER2 was upgraded.

Run ssh login.archer2.ac.uk (and to each of the individual login nodes login[1-4].archer2.ac.uk) and remove ALL offending keys from your ~/.ssh/known_hosts file. Keep doing this until you get the usual response.

ros@pumanew$ ssh login.archer2.ac.uk
PTY allocation request failed on channel 0
Comand rejected by policy. Not in authorised list
Connection to login.archer2.ac.uk closed.

Regards,
Ros.

3

Thanks, Ros. I was able to run ssh login.archer2.ac.uk and get the same result you posted. I cleared out the known_host offending keys and I also ran ssh login[1-4].archer2.ac.uk - I didn’t get the same result as you posted (i.e. the PTY allocation…) - should I have done? The run does now start however.

However, all the build tasks fail with:

Lmod has detected the following error: The following module(s) are unknown:
“cce/12.0.3”

Please check the spelling or version number. Also try “module spider …”
It is also possible your cache file is out-of-date; it may help to try:
$ module --ignore-cache load “cce/12.0.3”

Also make sure that all modulefiles written in TCL start with the string
#%Module

I tried module --ignore-cache load “cce/12.0.3” in Archer2 but this just returned the above error message. I can see in site/archer2.rc the command module load “cce/12.0.3”. When I run module spider in Archer2 there is no sign of cce/12.0.3 but this is cce/15.0.0. Should I change 12.0.3 to 15.0.0 in site/archer2.rc?

Thanks,

James

4

Hi James,

Yes you should get the standard PTY response I posted. What do you get?

You will also need to follow our instructions for updating suites following the ARCHER2 upgrade. You should have received an email from us after ARCHER2 returned to service. Details are available on our website (and on the announcement at the top of this page): Updating a UM suite after the ARCHER2 O/S upgrade

Regards,
Ros.

5

Hi Ros,

The response I got for ssh login[1-4].archer2.ac.uk was:

-bash-4.2$ ssh login4.archer2.ac.uk
The authenticity of host ‘login4.archer2.ac.uk (193.62.216.45)’ can’t be established.
ECDSA key fingerprint is SHA256:SwK9bZr4Iigrkj/mvC/4GhwEF5oKYN/sveLzwE3LGnA.
ECDSA key fingerprint is MD5:44:64:50:e7:8b:5c:11:5c:40:a1:b3:ff:0b:e7:a9:f4.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘login4.archer2.ac.uk,193.62.216.45’ (ECDSA) to the list of known hosts.
Permission denied (publickey).

-bash-4.2$ ssh login4.archer2.ac.uk
Permission denied (publickey).

I’m currently in the US - could this be causing a problem?

Thank you for the link re the Archer2 upgrade. I will review it and make the necessary changes.

Cheers,

James

6

Hi James,

It’s because you don’t have your .ssh/config set up quite right for it to use the correct key to login to individual login nodes.

Host login*.archer2.ac.uk        <= missing *
User jweber
IdentityFile ~/.ssh/id_rsa_archerum
ForwardX11 no
ForwardX11Trusted no

Regards,
Ros.

7

Hi Ros,

That has all worked, thank you for your help.

Cheers,

James