sysctl.d: set kernel.pid_max=4194304 on 64-bit systems

For CONFIG_BASE_FULL Linux kernels, the maximum number of proc/thread
IDs is set to 32768 by default. This default limit can be quite easily
hit during recovery on nodes with high OSD counts.
To avoid hitting the pid_max default limit, attempt to configure it to
4194304, which corresponds to the maximum limit possible on 64-bit
CONFIG_BASE_FULL kernels.

Fixes: http://tracker.ceph.com/issues/21929

Signed-off-by: David Disseldorp <[email protected]>

Author: ddiss

Diff for: CMakeLists.txt

@@ -589,6 +589,8 @@ if(WITH_SYSTEMD)
   add_subdirectory(systemd)
 endif()
 
+add_subdirectory(etc/sysctl)
+
 include(CTags)
 option(CTAG_EXCLUDES "Exclude files/directories when running ctag.")
 add_tags(ctags

Diff for: etc/sysctl/.gitignore

@@ -0,0 +1 @@
+90-ceph-osd.conf

Diff for: etc/sysctl/90-ceph-osd.conf renamed to etc/sysctl/90-ceph-osd.conf.in

@@ -1 +1,2 @@
 fs.aio-max-nr = 1048576
+@sysctl_pid_max@

Diff for: etc/sysctl/CMakeLists.txt

@@ -0,0 +1,8 @@
+if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "i386|i686|arm|ARM")
+  # 4194304 is the maximum limit possible on 64-bit CONFIG_BASE_FULL kernels.
+  # Keep the default for 32-bit systems.
+  set(sysctl_pid_max "kernel.pid_max = 4194304")
+endif()
+
+configure_file(90-ceph-osd.conf.in
+               ${CMAKE_CURRENT_SOURCE_DIR}/90-ceph-osd.conf @ONLY)