DataStax Agent configuration

Agent auto-connect

If you are adding an existing cluster to OpsCenter, and the nodes do not have the agent installed, OpsCenter displays a Fix Agents link next to the number of nodes. Clicking Fix Agents causes OpsCenter to attempt to install and start the agent on any nodes that do not have a running agent, as described in Automatic installation of DataStax agents and Installing DataStax agents.

If clicking Fix Agents did not work, there are a number of things that could prevent OpsCenter from successfully installing and starting the agent on the nodes. For example, if the agent was previously installed on the node and has an incorrect configuration, OpsCenter cannot connect to the agent. Some simple things to check if the agent fails to connect:

Verify the agent is able to start up without errors on the node. Look through the agent logs for errors.
Check the settings of the stomp_interface and stomp_port options for each agent to make sure they match and are pointing to the OpsCenter host and port, respectively.
Test that the OpsCenter host and port are accessible from the node. A firewall might be blocking access to the OpsCenter port, for example.
Verify that agents have the correct configuration settings for SSL communication if OpsCenter is configured to use SSL communication between itself and the agents.
Test that the SSH credentials you have entered in OpsCenter work on each node.
Verify JMX connectivity is enabled on the node.

In most environments, stomp_interface is the only property that will need to be explicitly configured, and this might happen automatically as previously mentioned. You can set most of these properties in the [agent_config] section of cluster_name.conf on the opscenterd machine and the properties propagate automatically to all agents. Some properties or some cases will require setting these properties directly in address.yaml on applicable agents.

The address.yaml configuration file

The address.yaml file contains configuration options for the DataStax Agent.

Note: As of version 5.1 of OpsCenter, the hosts option in address.yaml now determines which nodes the agent connects to. For further information on configuration changes and migration paths, see the Upgrade Guide.

address.yaml

The location of the address.yaml file depends on the type of installation:

Package installations: /var/lib/datastax-agent/conf/address.yaml
Tarball installations: install_location/conf/address.yaml

opscenterd.conf

The location of the opscenterd.conf file depends on the type of installation:

Location	Package	Installer (GUI or text mode)		Tarball
Location	Package	Service	No-service	Tarball
/etc/opscenter/opscenterd.conf	X	X
`install_location`/conf/opscenterd.conf			X	X

Options

hosts: The DataStax Enterprise node or nodes responsible for storing OpsCenter data. By default this will be the local node, but may be configured to store data on a separate cluster. The hosts option accepts an array of strings specifying the IP addresses of the node or nodes. For example, ["1.2.3.4"] or ["1.2.3.4", "1.2.3.5"]
alias: A name for the node to use as a label throughout OpsCenter.
restore_on_transfer_failure: Determines whether to allow a restore operation from S3 to continue after any file fails to download. Setting the value to 1 allows the restore operation to continue. The default setting is 0.
max-number-queued-files: Sets the maximum number of files to queue for uploading to a remote backup destination. Increasing this number impacts memory. The default setting is 100000.
stomp_interface: Reachable IP address of the opscenterd machine. The connection made will be on stomp_port.
stomp_port: The stomp_port used by opscenterd. The default setting is 61620.
local_interface: The IP used to identify the node. If broadcast_address is set in cassandra.yaml, this should be the same as that; otherwise, it is typically the same as listen_address in cassandra.yaml. A good check is to confirm that this address is the same as the address that nodetool ring outputs.
agent_rpc_interface: The IP that the agent HTTP server listens on. In a multiple region deployment, this is typically a private IP.
agent_rpc_broadcast_address: The IP that the central OpsCenter process uses to connect to the DataStax agent.
use_ssl: Whether or not to use SSL communication between the agent and opscenterd. Affects both the STOMP connection and agent HTTP server. Corresponds to [agents].use_ssl in opscenterd.conf. Setting this option to 1 turns on SSL connections. The default setting is 0.
cassandra_conf: The agent will attempt to auto-detect the location of the cassandra.yaml file via JMX, but if it cannot this needs to be set to the full path of cassandra.yaml. By default /etc/cassandra/cassandra.yaml on package installs or <install_location>/conf/cassandra.yaml on tarball installs.
cassandra_install_location: The location where Cassandra is installed for tarball installs if OpsCenter is unable to auto-detect the install location.
cassandra_log_location: The location of Cassandra's system.log file. This is only used for the diagnostics tarball, and should only be set if system.log is in a non-standard location.
tmp_dir: The location of the Backup Service staging directory for backups. The default location is /var/lib/datastax-agent/tmp.

Advanced options

metrics_enabled: Whether or not to collect and store metrics for the local node. Setting this option to 0 turns off metrics collection. The default setting is 1.
cassandra_port: Port used to connect to Cassandra. The default setting is 9042. This information will be sent by opscenterd for convenience, but can be configured locally as needed.
jmx_host: Host used to connect to local JMX server. The default setting is localhost. This information will be sent by opscenterd for convenience, but can be configured locally as needed.
jmx_port: Port used to connect to local JMX server. The default setting is 7199. This information will be sent by opscenterd for convenience, but can be configured locally as needed.
api_port: Port the local HTTP server will bind to. The default setting is 61621. This option needs to be identical across all agents, and set explicitly in opscenterd.conf if changed.

runs_sudo: Sets whether the DataStax Agent will be run using sudo. Setting this option to 0 means the agent will not use sudo, and the agent user will not run using elevated privileges. Setting this option to 1 means the agent will run using sudo, and elevated privileges.; The default setting is 1.
max_reconnect_time: Maximum delay in ms for an agent to attempt reconnecting to Cassandra. The default is 15000 ms (15 s).