`admin` cell: `exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:47836])[state=Opened] IOException: Connection reset`

[calestyo]

Hey.

With dCache 10.2.18 I'm getting since a while errors like these:

2025-12-29T02:14:25.365998+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 02:14:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:34048])[state=Opened] IOException: Connection reset
2025-12-29T03:30:03.142708+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 03:30:03+01:00 (admin) [] write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:34476]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T03:30:03.143446+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 03:30:03+01:00 (admin) [] Failed to shutdown console cleanly: write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:34476]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T05:45:02.750577+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 05:45:02+01:00 (admin) [] write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:41020]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T05:45:02.751854+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 05:45:02+01:00 (admin) [] Failed to shutdown console cleanly: write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:41020]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T07:30:03.312860+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 07:30:03+01:00 (admin) [] Failed to shutdown console cleanly: write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:53668]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T07:54:25.389741+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 07:54:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:58048])[state=Opened] IOException: Connection reset
2025-12-29T09:34:26.040013+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 09:34:26+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:45146])[state=Opened] IOException: Connection reset
2025-12-29T10:45:02.576446+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 10:45:02+01:00 (admin) [] Failed to shutdown console cleanly: write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:33584]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2025-12-29T16:00:02.079346+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 16:00:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:48672])[state=Opened] IOException: Connection reset
2025-12-29T20:40:01.807649+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-29 20:40:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:54954])[state=Opened] IOException: Connection reset
2025-12-30T06:20:02.683463+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-30 06:20:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:54508])[state=Opened] IOException: Connection reset
2025-12-30T10:20:01.845880+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-30 10:20:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:59198])[state=Opened] IOException: Connection reset
2025-12-30T13:00:02.700644+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-30 13:00:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:59710])[state=Opened] IOException: Connection reset
2025-12-30T21:19:26.105554+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-30 21:19:26+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:58498])[state=Opened] IOException: Connection reset
2025-12-31T01:00:02.734385+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-31 01:00:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:51816])[state=Opened] IOException: Connection reset
2025-12-31T01:19:25.276296+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-31 01:19:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:39628])[state=Opened] IOException: Connection reset
2025-12-31T07:20:02.405194+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-31 07:20:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:36638])[state=Opened] IOException: Connection reset
2025-12-31T08:39:25.379440+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-31 08:39:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:33056])[state=Opened] IOException: Connection reset
2025-12-31T16:09:25.584525+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2025-12-31 16:09:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:36158])[state=Opened] IOException: Connection reset
2026-01-01T00:50:01.504387+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-01 00:50:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:54650])[state=Opened] IOException: Connection reset
2026-01-01T13:20:01.609160+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-01 13:20:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:40826])[state=Opened] IOException: Connection reset
2026-01-01T21:30:01.654400+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-01 21:30:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:56910])[state=Opened] IOException: Connection reset
2026-01-01T23:50:01.926028+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-01 23:50:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:56224])[state=Opened] IOException: Connection reset
2026-01-02T07:09:25.910926+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-02 07:09:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:48002])[state=Opened] IOException: Connection reset
2026-01-03T13:17:01.623793+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-03 13:17:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:46574])[state=Opened] IOException: Connection reset
2026-01-03T13:44:25.177821+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-03 13:44:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:54774])[state=Opened] IOException: Connection reset
2026-01-03T15:00:01.866634+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-03 15:00:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:54606])[state=Opened] IOException: Connection reset
2026-01-03T22:59:25.347338+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-03 22:59:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:53416])[state=Opened] IOException: Connection reset
2026-01-04T02:24:25.700273+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-04 02:24:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:53060])[state=Opened] IOException: Connection reset
2026-01-04T23:39:25.649070+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-04 23:39:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:47836])[state=Opened] IOException: Connection reset
2026-01-05T10:29:25.241125+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-05 10:29:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:53664])[state=Opened] IOException: Connection reset
2026-01-05T15:40:01.930261+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-05 15:40:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:57248])[state=Opened] IOException: Connection reset
2026-01-05T16:17:01.928807+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-05 16:17:01+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:47694])[state=Opened] IOException: Connection reset
2026-01-05T20:00:02.540054+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-05 20:00:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:59960])[state=Opened] IOException: Connection reset
2026-01-05T22:15:02.488691+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-05 22:15:02+01:00 (admin) [] Failed to shutdown console cleanly: write(ChannelOutputStream[ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/[0:0:0:0:0:0:0:1]:46172]] SSH_MSG_CHANNEL_DATA) len=1 - channel already closed
2026-01-06T01:44:25.939483+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-06 01:44:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:39884])[state=Opened] IOException: Connection reset
2026-01-06T02:19:25.359072+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-06 02:19:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:59140])[state=Opened] IOException: Connection reset
2026-01-06T06:54:25.399608+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-06 06:54:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:36366])[state=Opened] IOException: Connection reset
2026-01-06T16:29:25.780850+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-06 16:29:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:60850])[state=Opened] IOException: Connection reset
2026-01-06T23:20:02.779291+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-06 23:20:02+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:58934])[state=Opened] IOException: Connection reset
2026-01-07T17:49:25.255568+01:00 lcg-lrz-dcache0 dcache@admin0[754881]: 2026-01-07 17:49:25+01:00 (admin) [] exceptionCaught(ServerSessionImpl[null@/[0:0:0:0:0:0:0:1]:58622])[state=Opened] IOException: Connection reset

Every 5 minutes so I run some checks via (currently still) Icinga, which do some stuff in the admin interface.
This means that it doesn't fail always but only sometimes.
Have run the very same checks since many years, the above errors never occurred.

The only thing that recently changed was upgrade from Debian bookworm to trixie and along that from OpenJDK 17 to 21.

Any ideas what that could be or how to debug?

Thanks,
Chris.