Ceph

This pack deploys a Ceph container in "demo" mode, where a single container runs all the required services. This is primarily for demonstration purposes and to provide a target for the ceph_rbd_csi pack.

NOTE: This pack is not suitable for production, and if the allocation is rescheduled all data written to Ceph will be lost! If you are interested in submitting an update to make this Ceph pack production-ready, the Nomad engineering team would enthusiastically review it!

Client Requirements

This pack can only be run on Nomad clients that have enabled volumes and privileged mode for the Docker task driver. In addition, you must have the rbd kernel module loaded:

$ sudo modprobe rbd
$ lsmod | grep rbd
rbd                   106496  0
libceph               327680  1 rbd

Without the kernel module loaded, plugins that consume Ceph will fail with errors like: modprobe: FATAL: Module rbd not found in directory

Variables

• job_name (string "ceph") - The name to use for the job.
• datacenters (list(string) ["dc1"]) - A list of datacenters in the region which are eligible for task placement.
• region (string "global") - The region where the job should be placed.
• ceph_image (string "ceph/daemon:latest-octopus") - The container image for Ceph.
• ceph_cluster_id (string "") - The Ceph cluster ID (will default to a random UUID).
• ceph_demo_uid (string "demo") - The UID for the Ceph demo.
• ceph_demo_bucket (string "example") - The bucket name for the Ceph demo.
• ceph_monitor_service_name (string "ceph-mon") - The Consul service name for the Ceph monitoring service.
• ceph_monitor_service_port (number 3300) - The port for the Ceph monitoring service to listen on.
• ceph_dashboard_service_name (string "ceph-dashboard") - The Consul service name for the Ceph dashboard service.
• ceph_dashboard_service_port (number 5000) - The port for the Ceph dashboard service to listen on.
• ceph_config_file (string "") - The full text of the Ceph demo configuration file. A reasonable demo will be provided by default.

constraints List of Objects

Nomad job specification constraints allow restricting the set of eligible nodes on which the tasks will run. This pack automatically configures the following required constraints:

• The task will run on Linux hosts only
• The task will run on hosts with the Docker driver's volumes enabled and allow_privileged set to true.

You can set additional constraints with the constraints variable, which takes a list of objects with the following fields:

• attribute (string) - Specifies the name or reference of the attribute to examine for the constraint.
• operator (string) - Specifies the comparison operator. The ordering is compared lexically.
• value (string) - Specifies the value to compare the attribute against using the specified operation.

Below is also an example of how to pass constraints to the CLI with the -var argument.

nomad-pack run -var 'constraints=[{"attribute":"$${meta.my_custom_value}","operator":">","value":"3"}]' packs/ceph

resources Object

• cpu (number 256) - Specifies the CPU required to run this task in MHz.
• memory (number 600) - Specifies the memory required in MB.