01-NodeAttributes.md

DCOS Toolkit - Mesos - Add node Attributes

• To use marathon constraints, we can specify attributes to every mesos node.
• Attributes are defined in key:value pairs and node can have multiple attributes.
• Attributes are useful to categorize the node, for example: nodes for DB servers can have attribute like 'SERVER_TYPE:DB' or 'DB_TYPE:MYSQL'
• Attributes are useful to add constraints on marathon apps to run on run on nodes with specific attributes.

Steps to add node attributes on mesos node

1. SSH on node

2. Create or edit file
   sudo vi /var/lib/dcos/mesos-slave-common

3. Add contents as :
   MESOS_ATTRIBUTES=<key1>:<value1>;<key2>:<value2>;...;<keyN>:<valueN>

   Note - multiple attributes are separated by semicolon [;].
   Example: MESOS_ATTRIBUTES=TYPE:DB;DB_TYPE:MONGO;

4. Stop dcos-mesos-slave service
   sudo systemctl stop dcos-mesos-slave

5. Remove link for latest slave metadata
   sudo rm -f /var/lib/mesos/slave/meta/slaves/latest

6. Start dcos-mesos-slave service
   sudo systemctl start dcos-mesos-slave

7. Check status of dcos-mesos-slave service
   sudo systemctl status dcos-mesos-slave

8. Wait for some time, node will be in HEALTHY state again.

9. Add app placement constraint with field = key and value = value

10. Verify attributes, run on any node
    curl -s http://leader.mesos:5050/state | jq '.slaves[]| .hostname ,.attributes'

    or Check DCOS UI Nodes => Select any Node => Details Tab

Automation Script

addNodeAttributes.sh