JClouds: How to attach a new volume to an AWS EC2 instance

Question

I am trying to attach a new volume to my instance using JClouds. But I can't find a way to do it.

    final String POLL_PERIOD_TWENTY_SECONDS = String.valueOf(SECONDS.toMillis(20));

    Properties overrides = new Properties();
    overrides.setProperty(ComputeServiceProperties.POLL_INITIAL_PERIOD, POLL_PERIOD_TWENTY_SECONDS);
    overrides.setProperty(ComputeServiceProperties.POLL_MAX_PERIOD, POLL_PERIOD_TWENTY_SECONDS);

    Iterable<Module> modules = ImmutableSet.<Module> of(new SshjSshClientModule(), new SLF4JLoggingModule());
    //Iterable<Module> modules = ImmutableSet.<Module> of(new SshjSshClientModule());

    ComputeServiceContext context = ContextBuilder.newBuilder("aws-ec2")
            .credentials("valid user", "valid password")
            .modules(modules)
            .overrides(overrides)
            .buildView(ComputeServiceContext.class);
    ComputeService computeService = context.getComputeService();

    // Ubuntu AMI
    Template template = computeService.templateBuilder()
            .locationId("us-east-1")
            .imageId("us-east-1/ami-7c807d14")
            .hardwareId("t1.micro")
            .build();

    // This line creates the volume but does not attach it
    template.getOptions().as(EC2TemplateOptions.class).mapNewVolumeToDeviceName("/dev/sdm", 100, true);

    Set<? extends NodeMetadata> nodes = computeService.createNodesInGroup("m456", 1, template);

    for (NodeMetadata nodeMetadata : nodes) {
        String publicAddress = nodeMetadata.getPublicAddresses().iterator().next();
        //String privateAddress = nodeMetadata.getPrivateAddresses().iterator().next();
        String username = nodeMetadata.getCredentials().getUser();
        String password = nodeMetadata.getCredentials().getPassword();
        // [...]
        System.out.println(String.format("ssh %s@%s  %s", username, publicAddress, password));
        System.out.println(nodeMetadata.getCredentials().getPrivateKey());
    }

How can I create an attach a volume to the directory "/var" ? How could I create the instance with more hard disk space ?

Answer 1

You can use the ElasticBlockStoreApi in jclouds for this. You have created the instance already, so create and attach the volume like this:

// Get node
NodeMetadata node = Iterables.getOnlyElement(nodes);

// Get AWS EC2 API
EC2Api ec2Api = computeServiceContext.unwrapApi(EC2Api.class);

// Create 100 GiB Volume
Volume volume = ec2Api.getElasticBlockStoreApi().get()
        .createVolumeInAvailabilityZone(zoneId, 100);

// Attach to instance
Attachment attachment = ec2Api.getElasticBlockStoreApi().get()
        .attachVolumeInRegion(region, volume.getId(), node.getId(), "/dev/sdx");

Now, you have an EBS volume attached, and the VM has a block device created for it, you just need to run the right commands to mount it on the /var directory, which will depend on your particular operating system. You can run a script like this:

// Run script on instance
computeService.runScriptOnNode(node.getId(),
        Statements.exec("mount /dev/sdx /var"));