Ceph

This is just a report about an annoying warning we keep getting every time our logs are rotated.

libust[8241/8241]: Warning: HOME environment variable not set. Disabling LTTng-UST per-user tracing. (in setup_local_apps() at lttng-ust-comm.c:305)

- I am running ceph 9.0.3 in SL6.7 (or Centos 6.7)

1. cat /etc/redhat-release
   Scientific Linux release 6.7 (Carbon)

1. ceph -v
   ceph version 9.0.3 (7295612d29f953f46e6e88812ef372b89a43b9da)

- logrotate is run daily in our cluster, and ceph logs have a specific config.

1. rpm -qf /etc/logrotate.d/ceph
   ceph-9.0.3-0.el6.x86_64

- Each time logrotate is executed, we received a daily notice with the message

ibust[8241/8241]: Warning: HOME environment variable not set. Disabling LTTng-UST per-user tracing. (in setup_local_apps() at lttng-ust-comm.c:305)

- It seems that logrotate for ceph invokes a 'service ceph reload' which is executed as

env -i PATH=/sbin:/usr/sbin:/bin:/usr/bin TERM=xterm-256color /etc/init.d/ceph reload

- The 'env -i' sets an empty environment, and that is why we keep receiving that message. Looking further, '/etc/init.d/ceph reload' actually runs something as '/usr/bin/ceph-conf -c /etc/ceph/ceph.conf -n mon<id> host' where ceph-conf is a binary using liblttng-ust.so.0

1. env -i /usr/bin/ceph-conf -c /etc/ceph/ceph.conf -n <id>
   libust[8241/8241]: Warning: HOME environment variable not set. Disabling LTTng-UST per-user tracing. (in setup_local_apps() at lttng-ust-comm.c:305)

1. file /usr/bin/ceph-conf
   /usr/bin/ceph-conf: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, stripped

1. ldd /usr/bin/ceph-conf
   (...)
   liblttng-ust.so.0 => /usr/lib64/liblttng-ust.so.0 (0x000000337da00000)

- To fix this, I had to set 'export HOME=/root' in /usr/lib64/ceph/ceph_common.sh