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Riak Mesos CLI / DCOS Riak

CLI and other tools for interacting with the Riak Mesos Framework.

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Requirements

Before getting started with the RMF, there are a few environment and system related requirements that are assumed for the remainder of this tutorial:

Note to DCOS Users

All of the below instructions will work for the dcos riak command, just replace riak-mesos with dcos riak. Some other differences will be pointed out in the corresponding sections.

Installation

Pip Install

Install the latest tag

DCOS v0.4.x Install

DCOS v0.3.2 Install

Create a Configuration File

Usage

Try executing riak-mesos, riak-mesos -h, or riak-mesos --help to output the usage instructions like so:

riak-mesos --help

Usage: riak-mesos [OPTIONS] COMMAND [ARGS]...

  Command line utility for the Riak Mesos Framework / DCOS Service. This
  utility provides tools for modifying and accessing your Riak on Mesos
  installation.

Options:
  --home DIRECTORY  Changes the folder to operate on.
  --config PATH     Path to JSON configuration file.
  -v, --verbose     Enables verbose mode.
  --debug           Enables very verbose / debug mode.
  --info            Display information.
  --version         Display version.
  --config-schema   Display config schema.
  --cluster TEXT    Changes the cluster to operate on.
  --node TEXT       Changes the node to operate on.
  --json            Enables json output.
  --insecure-ssl    Turns SSL verification off on HTTP requests
  --help            Show this message and exit.

Commands:
  cluster    Interact with Riak clusters
  config     Displays configuration
  director   Interact with an instance of Riak Mesos...
  framework  Interact with an instance of Riak Mesos...
  node       Interact with a Riak node

To get information about a sub-command, try riak-mesos <command> --help:

riak-mesos cluster --help
Usage: riak-mesos cluster [OPTIONS] COMMAND [ARGS]...

  Interact with Riak clusters

...

Commands:
  config            Gets or sets the riak.conf configuration for...
  config-advanced   Gets or sets the advanced.config...
  create            Creates a new cluster.
  destroy           Destroys a cluster.
  endpoints         Iterates over all nodes in cluster and prints...
  info              Gets current metadata about a cluster
  list              Retrieves a list of cluster names
  restart           Performs a rolling restart on a cluster.
  wait-for-service  Iterates over all nodes in cluster and...

Install the RMF

NOTE: This step is unecessary for DCOS users since the dcos package install automatically performs this step.

Run the following command to create a Marathon application with an id that matches the riak.framework-name configuration value:

riak-mesos framework install

To make deployment scripting easier, use the wait-for-service command to block until the framework is ready for service:

riak-mesos framework wait-for-service

Create a cluster

Let's start with a 3 node cluster. First check if any clusters have already been created, and then verify the configuration:

riak-mesos cluster list
riak-mesos cluster config
riak-mesos cluster config-advanced

Create the cluster object in the RMF metadata, and then instruct the scheduler to create 3 Riak nodes:

riak-mesos cluster create
riak-mesos node add --nodes 3
riak-mesos node list

After a few moments, we can verify that individual nodes are ready for service with:

riak-mesos node wait-for-service --node riak-default-1
riak-mesos node wait-for-service --node riak-default-2
riak-mesos node wait-for-service --node riak-default-3

Alternatively a shortcut to the above is:

riak-mesos cluster wait-for-service

To get connection information about each of the nodes directly, try this command:

riak-mesos cluster endpoints | python -m json.tool

The output should look similar to this:

{
    "riak-default-1": {
        "alive": true,
        "http_direct": "mesos-agent-1.com:31716",
        "pb_direct": "mesos-agent-1.com:31717",
        "status": "started"
    },
    "riak-default-2": {
        "alive": true,
        "http_direct": "mesos-agent-2.com:31589",
        "pb_direct": "mesos-agent-2.com:31590",
        "status": "started"
    },
    "riak-default-3": {
        "alive": true,
        "http_direct": "mesos-agent-3.com:31491",
        "pb_direct": "mesos-agent-3.com:31492",
        "status": "started"
    }
}

Inspecting Nodes

Now that the cluster is running, let's perform some checks on individual nodes. This first command will show the hostname and ports for http and protobufs, as well as the metadata stored by the RMF:

riak-mesos node info --node riak-default-1

To get the current ring membership and partition ownership information for a node, try:

riak-mesos node status --node riak-default-1 | python -m json.tool

The output of that command should yield results similar to the following if everything went well:

{
    "down": 0,
    "exiting": 0,
    "joining": 0,
    "leaving": 0,
    "nodes": [
        {
            "id": "riak-default-1@mesos-agent-1.com",
            "pending_percentage": null,
            "ring_percentage": 32.8125,
            "status": "valid"
        },
        {
            "id": "riak-default-2@mesos-agent-2.com",
            "pending_percentage": null,
            "ring_percentage": 32.8125,
            "status": "valid"
        },
        {
            "id": "riak-default-3@mesos-agent-3.com",
            "pending_percentage": null,
            "ring_percentage": 34.375,
            "status": "valid"
        }
    ],
    "valid": 3
}

Other useful information can be found by executing these commands:

riak-mesos node aae-status --node riak-default-1
riak-mesos node ringready --node riak-default-1
riak-mesos node transfers --node riak-default-1

Update the Cluster Configuration

You can customize the riak.conf and advanced.config for a cluster if necessary. Use riak-mesos-scheduler/master/priv/riak.conf.default and riak-mesos-scheduler/master/priv/advanced.config.default as templates. It is important that all of the values specified with {{...}} remain intact.

Once you have created your customized versions of these files, you can save them to the cluster using the following commands:

Update riak.conf

As an example, I've created a file called riak.more_logging.conf in which I've updated this line: log.console.level = debug

riak-mesos cluster config --file riak.more_logging.conf

Update advanced.config

Similarly the advanced.config can be updated like so:

riak-mesos cluster config-advanced --file /path/to/your/advanced.config

Note: If you already have nodes running in a cluster, you'll need to perform a riak-mesos cluster restart to force the cluster to pick up the new changes.

Restart the Cluster

If your Riak cluster is in a stable state (no active transfers, ringready is true), there are certain situations where you might want to perform a rolling restart on your cluster. Execute the following to restart your cluster:

riak-mesos node ringready --node riak-default-1
riak-mesos node transfers wait-for-service --node riak-default-1
riak-mesos cluster restart

Situations where a cluster restart is required include:

Create Bucket Types

Several newer features in Riak require the creation of bucket types. To see the current bucket types and their properties, use the following:

riak-mesos node bucket-type list --node riak-default-1 | python -m json.tool

Use this command to create a new bucket type with custom properties:

riak-mesos node bucket-type create --node riak-default-1 --bucket-type mytype --props '{"props":{"n_val": 3}}'

More information about specific bucket type properties can be found here: http://docs.basho.com/riak/latest/dev/advanced/bucket-types/.

A successful response looks like this:

{"mytype":{"success":true,"actions":{"create":"mytype created","activate":"mytype has been activated"}}}

To update an existing type, just modify the command and run it again:

riak-mesos node bucket-type create --node riak-default-1 --bucket-type mytype --props '{"props":{"n_val": 2}}'

Which should give something like this back:

{"mytype":{"success":true,"actions":{"update":"mytype updated"}}}

Install the Director

There are a few ways to access the Riak nodes in your cluster, including hosting your own HAProxy and keeping the config updated to include the host names and ports for all of the nodes. This approach can be problematic because the HAProxy config would need to be updated every time there is a change to one of the nodes in the cluster resulting from restarts, task failures, etc.

To account for this difficulty, we've created a smart proxy called the riak-mesos-director. The director should keep tabs on the current state of the cluster including all of the hostnames and ports, and it also provides a load balancer / proxy to spread load across all of the nodes.

To install the director as a marathon app with an id that matches your configured cluster name (default is default) + -director, simply run:

riak-mesos director install

Add Some Data

Assuming that the director is now running, we can now find an endpoint to talk to Riak with this command:

riak-mesos director endpoints

The output should look similar to this:

{
    "cluster": "default",
    "director_http": "mesos-agent-4.com:31694",
    "framework": "riak",
    "riak_http": "mesos-agent-4.com:31692",
    "riak_pb": "mesos-agent-4.com:31693"
}

Let's write a few keys to the cluster using the director:

RIAK_HTTP=$(riak-mesos director endpoints | python -c 'import sys, json; print json.load(sys.stdin)["riak_http"]')
curl -XPUT $RIAK_HTTP/buckets/test/keys/one -d "this is data"
curl -XPUT $RIAK_HTTP/buckets/test/keys/two -d "this is data too"

Scale up

When scaling a cluster up, you should attempt to do so days or even weeks before the additional load is expected to allow the cluster some time to transfer partitions around and stabilize. When you are ready to increase the node count, you can just run the node add command like so:

riak-mesos node add
riak-mesos node wait-for-service --node riak-default-4
riak-mesos node transfers wait-for-service --node riak-default-4

Check the status of the node and make sure it was successfully joined to the cluster using:

riak-mesos node status --node riak-default-4

Scale down

Scaling down requires the same patience as scaling up in that you should be waiting for transfers to complete between each node removal.

Let's remove all but one of the nodes by performing a remove on riak-default-2, riak-default-3, and riak-default-4, verifying the data and node status after each step.

riak-mesos node remove --node riak-default-4
riak-mesos node transfers wait-for-service --node riak-default-1
curl $RIAK_HTTP/buckets/test/keys/one


riak-mesos node remove --node riak-default-3
riak-mesos node transfers wait-for-service --node riak-default-1
curl $RIAK_HTTP/buckets/test/keys/two


riak-mesos node remove --node riak-default-2
riak-mesos node transfers wait-for-service --node riak-default-1
curl $RIAK_HTTP/buckets/test/keys/one
curl $RIAK_HTTP/buckets/test/keys/two

Uninstall RMF

The following commands can be used to remove part or all of the RMF.

DCOS Riak Uninstall

Follow these steps to cleanly remove riak from a DCOS cluster:

dcos riak director uninstall
dcos riak cluster destroy
dcos package uninstall riak