| post_title | menu_order | feature_maturity | enterprise |
|---|---|---|---|
Install and Customize |
0 |
preview |
no |
Cassandra for DC/OS is available in the Universe and can be installed by using either the web interface or the DC/OS CLI.
Prerequisites:
-
DC/OS and DC/OS CLI installed with a minimum of three agent nodes with eight GB of memory and ten GB of disk available on each agent.
-
Depending on your security mode, Cassandra requires a service authentication for access to DC/OS. For more information, see Configuring DC/OS Access for Cassandra.
Security mode Service Account Disabled Not available Permissive Optional Strict Required -
Ports 7000, 7001, 7199, 9042, and 9160 must be available.
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 three 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.
Install the Cassandra package. This may take a few minutes.
dcos package install cassandraThis command creates a new Cassandra cluster with three 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.
Note: You can also install Cassandra from the Universe > Packages tab of the DC/OS web interface. If you install Cassandra from the web interface, you must install the Cassandra DC/OS CLI subcommands separately. From the DC/OS CLI, enter:
dcos package install cassandra --cli
If you are ready to ship into production, you need to customize the deployment to suit the workload requirements of your applications. Customize the default deployment by creating an options JSON file, then pass it to dcos package install using the --options parameter.
Create a JSON options file named sample-cassandra.json:
{
"nodes": {
"count": 10,
"seeds": 3
}
}Install Cassandra with the configuration specified in the sample-cassandra.json file:
dcos package install --options=sample-cassandra.json cassandraThis cluster will have ten nodes and three seeds, instead of the default values of three nodes and two 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.
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 named sample-cassandra-minimal.json:
{
"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 two GB of memory and four GB of disk. 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.
Install Cassandra with the configuration specified in the sample-cassandra-minimal.json file:
dcos package install --options=sample-cassandra-minimal.json cassandraTo install multiple Cassandra clusters, create a JSON options file named sample-cassandra-multiple.json and specify a unique name for each installation:
{
"service": {
"name": "cassandra1"
}
}Install Cassandra with the configuration specified in the sample-cassandra-multiple.json file:
dcos package install cassandra --options=sample-cassandra-multiple.jsonIn 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