Docker
======

The easiest way to run Crail is to use Docker images. We provide two preconfigured
Docker images:

(1) TCP/DRAM: **apache/crail**
(2) RDMA/DRAM: **apache/crail_rdma**

If you want to run other or more complex configurations you can use either image
as a basis and provide your own configuration files.
Refer to :ref:`Own configurations` for details.

(1) and 2. share the following configuration parameters:

========================================    ======================   ==============================================
Property                                    Default Value            Description
========================================    ======================   ==============================================
:code:`NAMENODE_HOST`                       localhost                Namenode hostname/ip to bind to
:code:`NAMENODE_PORT`                       9060                     Namenode port to listen on
:code:`INTERFACE`                           eth0                     Datanode network interface to listen on
:code:`DATAPATH`                            /dev/hugepages/data      Datanode hugepage path to data
:code:`STORAGELIMIT`                        1073741824               Datanode Size (Bytes) of DRAM to provide
:code:`CACHEPATH`                           /dev/hugepages/cache     Client/Datanode hugepage path to buffer cache
:code:`CACHELIMIT`                            0                        Size (Bytes) of hugepage buffer cache
========================================    ======================   ==============================================

These properties can be specified as environment variables when
starting a Docker image with :code:`-e <property>=<value>`.

TCP image
---------

To run Crail you first need to start the namenode. For example

.. code-block:: bash

   docker run -it --network host -e NAMENODE_HOST=host02 -e INTERFACE=eth5 apache/crail namenode

starts a TCP namenode using Docker's host network configuration on host02 on interface eth5.
The TCP tier allows for other network configurations.
Refer to https://docs.docker.com/network/ for details.

Once the namenode has started start a Crail TCP storage tier (preferably on a different node).
For example


.. code-block:: bash

   docker run -it --network host -e NAMENODE_HOST=host02 -e INTERFACE=eth5 apache/crail datanode

starts a TCP datanode with 1GB of storage (default) listening on eth5. It is recommended
to put the data directory on a hugetlb mount. You can do this by passing an
mounted hugetlb directory on the host as a volume to Docker. For example


.. code-block:: bash

   docker run -it --network host -e NAMENODE_HOST=host02 -e INTERFACE=eth5 -v /dev/hugepages:/dev/hugepages apache/crail datanode

passes the hugetlb mount /dev/hugepages to the container.

RDMA image
----------

To run Crail/RDMA/DRAM you can start the namenode as follows:

.. code-block:: bash

    docker run -it --network host -e NAMENODE_HOST=host02 -e INTERFACE=eth5 --cap-add=IPC_LOCK --device=/dev/infiniband/uverbs0 --device=/dev/infiniband/rdma_cm -v /dev/hugepages:/dev/hugepages apache/crail_rdma namenode

This starts a namenode on host02 using the host's network on eth5. Note that the
uverbs device needs to match the interface.

To run a RDMA storage tier:


.. code-block:: bash

    docker run -it --network host -e NAMENODE_HOST=host02 -e INTERFACE=eth5 --cap-add=IPC_LOCK --device=/dev/infiniband/uverbs0 --device=/dev/infiniband/rdma_cm -v /dev/hugepages:/dev/hugepages apache/crail_rdma datanode

**Note:** *The RDMA docker image provides default RDMA provider libraries from Ubuntu 18.04.
They might not be compatible with your host's RDMA stack.
To install your own RDMA libraries use -v or create your own Docker image from crail_rdma.*

Own configurations
------------------

If you want to run more complex configurations that are not covered by the options above you have two options:

(1) Create your own Docker image by creating a Dockerfile and using the crail images as a source. You can then change the configuration by e.g. copying your own config into the image
(2) Pass your config as a volume with :code:`-v <local_path>:<docker_path>`