Using a9s Elasticsearch

This topic describes how developers use a9s Elasticsearch.

Use a9s Elasticsearch with an Application

To use a9s Elasticsearch with an application, create a service instance and bind the service instance to your application. For more information on managing service instances, see Managing Service Instances with the cf CLI.

View the a9s Elasticsearch Service

After the service is installed, you can see the a9s-elasticsearch5 and its service plans appear in your CF marketplace. Run cf marketplace to see the service listing:

$ cf marketplace
Getting services from marketplace in org test / space test as admin...
OK
service               plans                                                     description
a9s-elasticsearch5    elasticsearch-single-small, elasticsearch-cluster-small,  This is the a9s Elasticsearch 5 service.
                      elasticsearch-single-big, elasticsearch-cluster-big

Create a Service Instance

To provision an Elasticsearch database, run cf create-service. For example:

$ cf create-service a9s-elasticsearch5 elasticsearch-single-small my-elasticsearch-service

Depending on your infrastructure and service broker utilization, it may take several minutes to create the service instance.

Run the cf services command to view the creation status. This command displays a list of all your service instances. To view the status of a specific service instance, run cf service NAME-OF-YOUR-SERVICE.

Bind an Application to a Service Instance

After your database is created, run cf bind-service to bind the service to your application:

$ cf bind-service a9s-elasticsearch-app my-elasticsearch5-service

Restage or Restart Your Application

To enable your application to access the service instance, run cf restage or cf restart to restage or restart your application.

Obtain Service Instance Access Credentials

After a service instance is bound to an application, the credentials of your Elasticsearch database are stored in the environment variables of the application. Run cf env APP-NAME to display the environment variables.

You can find the credentials in the VCAP_SERVICES key.

$ cf env a9s-elasticsearch-app
Getting env variables for app a9s-elasticsearch-app in org test / space test as admin...
OK

System-Provided:
{
  "VCAP_SERVICES": {
   "a9s-elasticsearch5": [
    {
      "credentials": {
       "host": [
        "EXAMPLE_HOST"
       ],
       "hosts": [
        "EXAMPLE_HOST"
       ],
       "password": "EXAMPLE_USER",
       "username": "EXAMPLE_PASSWORD",
       "scheme": "http",
       "port": 9200
     },
     "label": "a9s-elasticsearch5",
     "name": "my-elasticsearch-service",
     "plan": "elasticsearch-cluster-small",
     "tags": [
      "searchengine"
     ]
    }
   ]
  }
}
...

You can use the host, username and password values to connect to your database with a Elasticsearch client.

Best Practices

There are some best practices for using service binding information in apps in a separate document.

Delete an a9s Elasticsearch Service Instance

WARNING: Before deleting a service instance, you must backup data stored in your database. This operation cannot be undone and all the data is lost when the service is deleted.

Before you can delete a service instance, you must unbind it from all apps.

List Available Services

Run cf services to list your available services.

$ cf services

Getting services in org test / space test as admin...
OK

name                       service              plan                         bound apps              last operation
my-elasticsearch-service   a9s-elasticsearch5   elasticsearch-single-small   a9s-elasticsearch-app   create succeeded

This example shows that my-elasticsearch-service is bound to the a9s-elasticsearch-app application.

Unbind a Service Instance

Run cf unbind-service to unbind the service from your application.

$ cf unbind-service a9s-elasticsearch-app my-elasticsearch-service

Delete a Service Instance

After unbinding the service, it is no longer bound to an application. Run cf delete-service to delete the service:

$ cf delete-service my-elasticsearch-service

It may take several minutes to delete the service. Deleting a service deprovisions the corresponding infrastructure resources. Run the cf services command to view the deletion status.

Upgrade the Service Instance to another Service Plan

Once created, you can upgrade your service instance to another, larger service plan. A larger service plan provides more CPU, RAM and storage. For more information, see the Update a Service Instance of the Managing Service Instances with the cf CLI topic.

$ cf update-service my-elasticsearch-service -p a-bigger-plan

Here are the plans you can upgrade to depending on the one you are currently using:

  • If you are currently using the elasticsearch-single-small plan, you can upgrade to the elasticsearchgodb-single-big plan.

  • If you are currently using the elasticsearch-cluster-small plan, you can upgrade to the elasticsearch-cluster-big plan.

Add a Graphite Endpoint

If you want to monitor your service with Graphite, you can set an endpoint to where to information will be sent with the cf update-service command. This command expects the -c flag and a JSON string containing the graphite and metrics_prefix keys. Depending on your graphite provider the metrics_prefix might require that each metrics must start with an API key in their name. You can also change the interval within the data is send to the endpoint. Do to this modify interval the default is 10s.

$ cf update-service my-elasticsearch-service -c '{ "graphite": ["yourspace.your-graphite-endpoint.com:12345"], "metrics_prefix": "your-api-key.my-cluster-elasticsearch", "interval": "5"}'

Add a Syslog Endpoint

The cf update-service command used with the -c flag can let you stream your syslog to a third-party service. In this case, the command expects a JSON string containing the syslog key. You can also change the interval for the syslog with the same key used to specify graphite interval.

$ cf update-service my-elasticsearch-service -c '{ "syslog": ["logs4.your-syslog-endpoint.com:54321"], "interval": "5" }'

Enable Custom Plugins

You can use the cf update-service command with the -c flag to enable plugins on demand such as the analysis-phonetic plugin which convert tokens to their phonetic representation using Soundex, Metaphone, and a variety of other algorithms.

To enable the analysis phonetic plugin you would use the following command:

$ cf update-service my-elasticsearch-service -c '{"plugins": ["analysis-phonetic"]}'

The currently available plugins are:

  • repository-s3 (enabled by default, cannot be disabled)
  • repository-azure (enabled by default, cannot be disabled)
  • analysis-phonetic

Cloud Foundry Application Security Groups

This topic describes how to check whether a security group was created.

Each a9s Data Service will automatically create and update Cloud Foundry security groups in order to protected service instances to be accessed by applications not running in the same Cloud Foundry applications space. To get a better understanding about Security Groups you can have a look on the Understanding Application Security Groups topic.

Get Service Instance GUID

Run cf service INSTANCE_NAME --guid to get the guid of the service instance.

$ cf service my-elasticsearch --guid
ca16f111-5073-40b7-973a-156c75dd3028

Check available Security Groups

To see all available security groups use cf security-groups.

$ cf security-groups
Getting security groups as demo@anynines.com
OK

     Name                                         Organization     Space
#0   public_networks
#1   dns
#2   tcp_open
#3   guard_432fb752-876d-443b-a311-a075f4df2237   demonstrations   demo
#4   guard_ca16f111-5073-40b7-973a-156c75dd3028   demonstrations   demo

There you can see a security group named guard_ca16f111-5073-40b7-973a-156c75dd3028 was successfully created.

NOTE: in some circumstances the connection between the application and the service instance is not possible, in this case check if a security group was created.

Backup and Restore Service Instances

a9s Elasticsearch provides an easy way to create backups and restore if needed. For a more detailed description, please see the a9s Service Dashboard documentation.

Make a Service Instance Locally Available

It is possible to access any of the a9s Data Services locally. That means you can connect with a local client to the service for any purpose such as debbuging. CF provides a smart way to create SSH forward tunnels via a pushed application. For more information about this feature see the Accessing Apps with SSH section of the CF documentation.

First of all you must have an application bound to the service. How to do this see Bind an Application to a Service Instance.

NOTE: cf ssh support must be enabled in the platform. Ask your administrator if you are not sure.

Get The Service Url and Credentials

When you follow this instructions Obtain Service Instance Access Credentials you will get the hostname of the service and the user credentials.

$ cf env a9s-elasticsearch-app
Getting env variables for app a9s-elasticsearch-app in org test / space test as admin...
OK

System-Provided:
{
  "VCAP_SERVICES": {
   "a9s-elasticsearch5": [
    {
      "credentials": {
       "host": [
        "d67901c.service.dc1.a9svs"
       ],
       "password": "a9s-brk-usr",
       "username": "a9s-password"
     },
     "label": "a9s-elasticsearch5",
     "name": "my-elasticsearch-service",
     "plan": "elasticsearch-cluster-small"
    }
   ]
  }
}
...

Notice the host d67901c.service.dc1.a9svs, the username a9s-brk-usr and the password a9s-password. You will need this in the next step.

Create a Tunnel to The Service

With the cf ssh as mentioned before you can create a ssh forward tunnel to the management dashboard. Use port 9200 to connect to the a9s Elasticsearch Instance.

$ cf ssh a9s-elasticsearch-app -L 9200:d67901c.service.dc1.a9svs:9200
vcap@956aaf4e-6da9-4f69-4b1d-8e631a403312:~$

When the ssh tunnel is open you can access the instance over the address localhost:9200.

NOTE: Don't forget to close the session with exit.

Setup Disk Usage Alerts

Each service comes with the a9s Parachute. This component monitors ephemeral and persistent disk usage. See the a9s Parachute documentation how to configure the component.