The next leap second will occur on June 30th, 2015 at 23:59:60 UTC. The last leap second in 2012 unveiled a livelock in the Linux kernel. This was fixed in Linux 3.4 and backported to older kernels with these two fixes:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6b43ae8a619d17c4935c3320d2ef9e92bdeed05d
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6b1859dba01c7
It needs to be checked that all precise hosts have a kernel running with these patches.
In addition, the Java developers also changed their clock-handling: https://bugs.openjdk.java.net/browse/JDK-6900441
These fixed OpenJDK packages should all be rolled out as part of previous security updates, but that needs to be double-checked.
Java 6
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The Java fix is present in all our openjdk-7 packages and the few systems with a openjdk-8 backport. This covers the complex services like Hadoop, Cassandra and Elastic.
However, Oracle didn't backport the fix to openjdk-6. The following systems use openjdk-6. In the worst case we need to restart some services, but possibly most of these should be moved to Java 7 anyway (e.g. lanthanum, since other part of Jenkins use Java 7 already).
[] labcontrol2001.wikimedia.org
[] ytterbium.wikimedia.org
[] labsdb1004.eqiad.wmnet
[] zirconium.wikimedia.org
[] labsdb1006.eqiad.wmnet
[X] lanthanum.eqiad.wmnet - T103491
In addition three further systems have openjdk-6 installed, but the standard Java is based on 7 (based on java -version). I'll clean these up:
[] nembus.wikimedia.org
[] neptunium.wikimedia.org
[X] gallium.wikimedia.org - T103491