- Added a sysctl configuration option for passing ceph specific

runtime flags.
       - Modified config.yaml to expose the sysctl option, by default is ""
       - Synced sysctl from charmhelpers

config.yaml

@@ -121,3 +121,9 @@ options:
       order for this charm to function correctly, the privacy extension must be
       disabled and a non-temporary address must be configured/available on
       your network interface.
+  sysctl:
+    type: string
+    default: ""
+    description: |
+     YAML formatted associative array of sysctl values, e.g.:
+      '{ kernel.pid_max : 4194303 }'

hooks/charmhelpers/core/sysctl.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+__author__ = 'Jorge Niedbalski R. <jorge.niedbalski@canonical.com>'
+
+import yaml
+
+from subprocess import check_call
+
+from charmhelpers.core.hookenv import (
+    log,
+    DEBUG,
+)
+
+
+def create(sysctl_dict, sysctl_file):
+    """Creates a sysctl.conf file from a YAML associative array
+
+    :param sysctl_dict: a dict of sysctl options eg { 'kernel.max_pid': 1337 }
+    :type sysctl_dict: dict
+    :param sysctl_file: path to the sysctl file to be saved
+    :type sysctl_file: str or unicode
+    :returns: None
+    """
+    sysctl_dict = yaml.load(sysctl_dict)
+
+    with open(sysctl_file, "w") as fd:
+        for key, value in sysctl_dict.items():
+            fd.write("{}={}\n".format(key, value))
+
+    log("Updating sysctl_file: %s values: %s" % (sysctl_file, sysctl_dict),
+        level=DEBUG)
+
+    check_call(["sysctl", "-p", sysctl_file])

hooks/hooks.py

@@ -36,6 +36,8 @@ from charmhelpers.fetch import (
     filter_installed_packages,
 )
 
+from charmhelpers.core.sysctl import create as create_sysctl
+
 from utils import (
     render_template,
     get_host_ip,
@@ -110,6 +112,10 @@ def config_changed():
     if config('prefer-ipv6'):
         assert_charm_supports_ipv6()
 
+    sysctl_dict = config('sysctl')
+    if sysctl_dict:
+        create_sysctl(sysctl_dict, '/etc/sysctl.d/50-ceph-osd-charm.conf')
+
     e_mountpoint = config('ephemeral-unmount')
     if (e_mountpoint and ceph.filesystem_mounted(e_mountpoint)):
         umount(e_mountpoint)