| post_title | menu_order | feature_maturity | enterprise |
|---|---|---|---|
Install and Customize |
20 |
preview |
no |
In Enterprise DC/OS strict security mode, Cassandra requires a service account. In permissive, a service account is optional. Only someone with superuser permission can create the service account. Refer to Provisioning Cassandra for instructions.
Prior to installing a default cluster, ensure that your DC/OS cluster has at least 3 agent nodes with 8 Gb of memory and 10 Gb of disk available on each agent. Also, ensure that ports 7000, 7001, 7199, 9042, and 9160 are available.
To start a default cluster, run the following command on the DC/OS CLI. The default installation may not be sufficient for a production deployment, but all cluster operations will work. If you are planning a production deployment with 3 replicas of each value and local quorum consistency for read and write operations (a very common use case), this configuration is sufficient for development and testing purposes and it may be scaled to a production deployment.
$ dcos package install cassandra
This command creates a new Cassandra cluster with 3 nodes. Two clusters cannot share the same name, so installing additional clusters beyond the default cluster requires customizing the name at install time for each additional instance. See the Custom Installation section for more information.
If you have more than one Cassandra cluster, use the --name argument after install time to specify which Cassandra instance to query. All dcos cassandra CLI commands accept the --name argument. If you do not specify a service name, the CLI assumes the default value, cassandra.
If you are ready to ship into production, you will likely need to customize the deployment to suit the workload requirements of your application(s). Customize the default deployment by creating a JSON file, then pass it to dcos package install using the --options parameter.
Sample JSON options file named sample-cassandra.json:
{
"nodes": {
"count": 10,
"seeds": 3
}
}
The command below creates a cluster using sample-cassandra.json:
$ dcos package install --options=sample-cassandra.json cassandra
This cluster will have 10 nodes and 3 seeds instead of the default values of 3 nodes and 2 seeds. See the Configuration Options section for a list of fields that can be customized via an options JSON file when the Cassandra cluster is created.
You may wish to install Cassandra on a local DC/OS cluster for development or testing purposes. For this, you can use dcos-vagrant. As with the default installation, you must ensure that ports 7000, 7001, 7199, 9042, and 9160 are available.
Note: This configuration will not support replication of any kind, but it may be sufficient for early stage evaluation and development.
To start a minimal cluster with a single node, create a JSON options file that contains the following:
{
"service" : {
"cpus": 0.1,
"mem": 512,
"heap": 256
},
"nodes": {
"cpus": 0.5,
"mem": 2048,
"disk": 4096,
"heap": {
"size": 1024,
"new": 100
},
"count": 1,
"seeds": 1
},
"executor" : {
"cpus": 0.1,
"mem": 512,
"heap": 256
},
"task" : {
"cpus": 0.1,
"mem": 128
}
}
This will create a single node cluster with 2 Gb of memory and 4Gb of disk. Note that you will need an additional 512 Mb for the DC/OS Apache Cassandra Service executor and 128 Mb for clusters tasks. The DC/OS Apache Cassandra Service scheduler needs 512 MB to run, but it does not need to be deployed on the same host as the node.
Installing multiple Cassandra clusters is identical to installing a Cassandra cluster with a custom configuration as described above. Use a JSON options file to specify a unique name for each installation:
$ cat cassandra1.json
{
"service": {
"name": "cassandra1"
}
}
$ dcos package install cassandra --options=cassandra1.json
In order to avoid port conflicts, by default you cannot collocate more than one Cassandra instance on the same node.
When the DC/OS Cassandra service is initially installed it will generate an installation plan as shown below. You can view, pause, and resume installation via the REST API. See the REST API authentication section of the REST API Reference for information on how this request must be authenticated.
{
"errors": [],
"phases": [
{
"steps": [
{
"id": "738122a7-8b52-4d45-a2b0-41f625f04f87",
"message": "Reconciliation complete",
"name": "Reconciliation",
"status": "Complete"
}
],
"id": "0836a986-835a-4811-afea-b6cb9ddcd929",
"name": "Reconciliation",
"status": "Complete"
},
{
"id": "e90ad90b-fd71-4a1d-a63b-599003ea46f5",
"name": "Sync Data Center",
"steps": [],
"status": "Complete"
},
{
"steps": [
{
"id": "440485ec-eba2-48a3-9237-b0989dbe9f68",
"message": "Deploying Cassandra node node-0",
"name": "node-0",
"status": "Complete"
},
{
"id": "84251eb9-218c-4700-a03c-50018b90d5a8",
"message": "Deploying Cassandra node node-1",
"name": "node-1",
"status": "InProgress"
},
{
"id": "aad765fe-5aa5-4d4e-bf66-abbb6a15e125",
"message": "Deploying Cassandra node node-2",
"name": "node-2",
"status": "Pending"
}
],
"id": "c4f61c72-038d-431c-af73-6a9787219233",
"name": "Deploy",
"status": "InProgress"
}
],
"status": "InProgress"
}
The plan can be viewed from the API via the REST endpoint. A curl example is provided below.
$ curl -H "Authorization: token=$AUTH_TOKEN" http://<dcos_url>/service/cassandra/v1/plan
If there are any errors that prevent installation, these errors are dispayed in the errors list. The presence of errors indicates that the installation cannot progress. See the Troubleshooting section for information on resolving errors.
The first phase of the installation plan is the reconciliation phase. This phase ensures that the DC/OS Apache Cassandra service maintains the correct status for the Cassandra nodes that it has deployed. Reconciliation is a normal operation of the DC/OS Apache Cassandra Service and occurs each time the service starts. See the Mesos documentation for more information.
The second phase of the installation is the deploy phase. This phase will deploy the requested number of Cassandra nodes. Each step in the phase represents an individual Cassandra node. In the plan shown above the first node, node-0, has been deployed, the second node, node-1, is in the process of being deployed, and the third node, node-2, is pending deployment based on the completion of node-1.
In order to pause installation, issue a REST API request as shown below. The installation will pause after completing installation of the current node and wait for user input.
$ curl -X POST -H "Authorization: token=$AUTH_TOKEN" http:/<dcos_url>/service/cassandra/v1/plan/interrupt
If the installation has been paused, the REST API request below will resume installation at the next pending node.
$ curl -X POST -H "Authorization: token=$AUTH_TOKEN" http://<dcos_url>/service/cassandra/v1/plan/continue