Enable bootstrap memory lock

- update pam_limits for bootstrap memory lock
- add entry for the elasticsearch user for maximum number of open files
- ensure Ubuntu uses the limits.conf file for init.d
- set MAX_LOCKED_MEMORY in /etc/default/elasticsearch,
which is required for bootstrap memory lock to work successfully.
- remove commented lines that make changes to pam_limits; these do
not appear to be required.

Closes elastic#94

README.md

@@ -122,8 +122,8 @@ Check out our [examples repository](https://github.com/elastic/azure-marketplace
     </td><td><code>""</code></td></tr>
 
   <tr><td>esHeapSize</td><td>integer</td>
-    <td>The size, in megaytes, of memory to allocate on each Elasticsearch node for the JVM heap. If unspecified, 50% of the available memory will be allocated to Elasticsearch heap, up to a maximum of 31744 MB. 
-    Take a look at <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/heap-size.html" target="_blank">the Elasticsearch documentation</a> for more information.  <strong>This is an expert level feature</strong>
+    <td>The size, in megabytes, of memory to allocate on each Elasticsearch node for the JVM heap. If unspecified, 50% of the available memory will be allocated to Elasticsearch heap, up to a maximum of 31744MB (~32GB). 
+    Take a look at <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/heap-size.html" target="_blank">the Elasticsearch documentation</a> for more information.  <strong>This is an expert level feature - setting a heap size larger than available memory on the Elasticsearch VM SKU will fail the deployment.</strong>
     </td><td><code>0</code></td></tr>
 
   <tr><td>kibana</td><td>string</td>

src/mainTemplate.json

@@ -122,7 +122,7 @@
       "type": "int",
       "defaultValue": 0,
       "metadata": {
-        "description": "The size, in megabytes, of memory to allocate on each Elasticsearch node for the JVM heap. If unspecified, 50% of the available memory will be allocated to Elasticsearch heap, up to a maximum of 31744 MB."
+        "description": "The size, in megabytes, of memory to allocate on each Elasticsearch node for the JVM heap. If unspecified, 50% of the available memory will be allocated to Elasticsearch heap, up to a maximum of 31744MB (~32GB)."
       }
     },
     "kibana": {

src/scripts/elasticsearch-ubuntu-install.sh

@@ -779,13 +779,13 @@ configure_elasticsearch_yaml()
     fi
 
     # Swap is disabled by default in Ubuntu Azure VMs, no harm in adding memory lock
-    # if dpkg --compare-versions "$ES_VERSION" ">=" "2.4.0"; then
-    #     log "[configure_elasticsearch_yaml] Setting bootstrap.memory_lock: true"
-    #     echo "bootstrap.memory_lock: true" >> $ES_CONF
-    # else
-    #     log "[configure_elasticsearch_yaml] Setting bootstrap.mlockall: true"
-    #     echo "bootstrap.mlockall: true" >> $ES_CONF
-    # fi
+    if dpkg --compare-versions "$ES_VERSION" ">=" "2.4.0"; then
+        log "[configure_elasticsearch_yaml] Setting bootstrap.memory_lock: true"
+        echo "bootstrap.memory_lock: true" >> $ES_CONF
+    else
+        log "[configure_elasticsearch_yaml] Setting bootstrap.mlockall: true"
+        echo "bootstrap.mlockall: true" >> $ES_CONF
+    fi
 }
 
 configure_elasticsearch()
@@ -834,14 +834,20 @@ configure_os_properties()
     # Increase maximum mmap count
     echo "vm.max_map_count = 262144" >> /etc/sysctl.conf
 
-    # Verify this is necessary on azure
-    # ML: 80% certain i verified this but will do so again
-    #echo "elasticsearch    -    nofile    65536" >> /etc/security/limits.conf
-    #echo "elasticsearch     -    memlock   unlimited" >> /etc/security/limits.conf
-    #echo "session    required    pam_limits.so" >> /etc/pam.d/su
-    #echo "session    required    pam_limits.so" >> /etc/pam.d/common-session
-    #echo "session    required    pam_limits.so" >> /etc/pam.d/common-session-noninteractive
-    #echo "session    required    pam_limits.so" >> /etc/pam.d/sudo
+    # Update pam_limits for bootstrap memory lock
+    echo "# allow user 'elasticsearch' mlockall" >> /etc/security/limits.conf
+    echo "elasticsearch soft memlock unlimited" >> /etc/security/limits.conf
+    echo "elasticsearch hard memlock unlimited" >> /etc/security/limits.conf
+
+    # Required for bootstrap memory lock
+    echo "MAX_LOCKED_MEMORY=unlimited" >> /etc/default/elasticsearch
+
+    # Maximum number of open files for elasticsearch user
+    echo "elasticsearch - nofile 65536" >> /etc/security/limits.conf
+
+    # Ubuntu ignores the limits.conf file for processes started by init.d by default, so enable them
+    echo "session    required   pam_limits.so" >> /etc/pam.d/su
+
     log "[configure_os_properties] configured operating system level configuration"
 }