Chinese Hackers

I am running fail2ban since November 2017 and all unsuccessful attempts to log-in to sshd are monitored. Breaking down these attempts according country shows that Chinese IP addresses are coming first here.

The numbers are:

27639    China
13589    United States
8641     France
3985     India
3418     Korea
3217     Brazil
2940     Canada
2419     Germany
2157     Russian Federation
1988     Indonesia

fail2ban_breakdown_country

The distribution of total attacks per month is as depicted below:
ipBlockPerMonth
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slurmctld showing nodes as ‘drain’

Recently one node was changed from octacore to hexacore. Since that time sinfo showed this node in STATE drain. Stopping and restarting slurmctld did not resolve the issue. Log file /var/log/slurm-llnl/slurmctld.log showed

[2019-12-31T23:57:52.588] error: Node X appears to have a different slurm.conf than the slurmctld.  This could cause issues with communication and functionality.  Please review both files and make sure they are the same.  If this is expected ignore, and set DebugFlags=NO_CONF_HASH in your slurm.conf.

This hinted that some caching is the culprit. Entry

StateSaveLocation=/var/lib/slurm-llnl/slurmctld

shows where slurmctld stores state. Removing the files in that directory and restarting slurmctld solves the problem.