ceph-deploy -- Deploy Ceph with minimal infrastructure

ceph-deploy is a way to deploy Ceph relying on just SSH access to the servers, sudo, and some Python. It runs fully on your workstation, requiring no servers, databases, or anything like that.

If you set up and tear down Ceph clusters a lot, and want minimal extra bureaucracy, this is for you.

It is not a generic deployment system, it is only for Ceph, and is designed for users who want to quickly get Ceph running with sensible initial settings without the overhead of installing Chef, Puppet or Juju.

It does not handle client configuration beyond pushing the Ceph config file and users who want fine-control over security settings, partitions or directory locations should use a tool such as Chef or Puppet.

Setup

To get the source tree ready for use, run this once:

./bootstrap

You can symlink the ceph-deploy script in this somewhere convenient (like ~/bin), or add the current directory to PATH, or just always type the full path to ceph-deploy.

ceph-deploy at a minimum requires that the machine from which the script is being run can ssh as root without password into each Ceph node.

To enable this generate a new ssh keypair for the root user with no passphrase and place the public key (id_rsa.pub or id_dsa.pub) in:

/root/.ssh/authorized_keys

and ensure that the following lines are in the sshd config:

PermitRootLogin yes PermitEmptyPasswords yes

The machine running ceph-deploy does not need to have the Ceph packages installed unless it needs to admin the cluster directly using the ceph command line tool.

Managing an existing cluster

You can use ceph-deploy to provision nodes for an existing cluster. To grab a copy of the cluster configuration file (normally ceph.conf):

ceph-deploy config pull HOST

You will usually also want to gather the encryption keys used for that cluster:

ceph-deploy gatherkeys MONHOST

At this point you can skip the steps below that create a new cluster (you already have one) and optionally skip instalation and/or monitor creation, depending on what you are trying to accomplish.

Creating a new cluster

Creating a new configuration

To create a new configuration file and secret key, decide what hosts will run ceph-mon, and run:

ceph-deploy new MON [MON..]

listing the hostnames of the monitors. Each MON can be

• a simple hostname. It must be DNS resolvable without the fully qualified domain name.
• a fully qualified domain name. The hostname is assumed to be the leading component up to the first ..
• a HOST:FQDN pair, of both the hostname and a fully qualified domain name or IP address. For example, foo, foo.example.com, foo:something.example.com, and foo:1.2.3.4 are all valid. Note, however, that the hostname should match that configured on the host foo.

The above will create a ceph.conf and ceph.mon.keyring in your current directory.

Edit initial cluster configuration

You want to review the generated ceph.conf file and make sure that the mon_host setting contains the IP addresses you would like the monitors to bind to. These are the IPs that clients will initially contact to authenticate to the cluster, and they need to be reachable both by external client-facing hosts and internal cluster daemons.

Installing packages

To install the Ceph software on the servers, run:

ceph-deploy install HOST [HOST..]

This installs the current default stable release. You can choose a different release track with command line options, for example to use a release candidate:

ceph-deploy install --testing HOST

Or to test a development branch:

ceph-deploy install --dev=wip-mds-now-works-no-kidding HOST [HOST..]

Deploying monitors

To actually deploy ceph-mon to the hosts you chose, run:

ceph-deploy mon create HOST [HOST..]

Without explicit hosts listed, hosts in mon_initial_members in the config file are deployed. That is, the hosts you passed to ceph-deploy new are the default value here.

Gather keys

To gather authenticate keys (for administering the cluster and bootstrapping new nodes) to the local directory, run:

ceph-deploy gatherkeys HOST [HOST...]

where HOST is one of the monitor hosts.

Once these keys are in the local directory, you can provision new OSDs etc.

Deploying OSDs

To prepare a node for running OSDs, run:

ceph-deploy osd create HOST:DISK[:JOURNAL] [HOST:DISK[:JOURNAL] ...]

After that, the hosts will be running OSDs for the given data disks. If you specify a raw disk (e.g., /dev/sdb), partitions will be created and GPT labels will be used to mark and automatically activate OSD volumes. If an existing partition is specified, the partition table will not be modified. If you want to destroy the existing partition table on DISK first, you can include the --zap-disk option.

If there is already a prepared disk or directory that is ready to become an OSD, you can also do:

ceph-deploy osd activate HOST:DIR[:JOURNAL] [...]

This is useful when you are managing the mounting of volumes yourself.

Admin hosts

To prepare a host with a ceph.conf and ceph.client.admin.keyring keyring so that it can administer the cluster, run:

ceph-deploy admin HOST [HOST ...]

Forget keys

The new and gatherkeys put some Ceph authentication keys in keyrings in the local directory. If you are worried about them being there for security reasons, run:

ceph-deploy forgetkeys

and they will be removed. If you need them again later to deploy additional nodes, simply re-run:

ceph-deploy gatherkeys HOST [HOST...]

and they will be retrieved from an existing monitor node.

Multiple clusters

All of the above commands take a --cluster=NAME option, allowing you to manage multiple clusters conveniently from one workstation. For example:

ceph-deploy --cluster=us-west new
vi us-west.conf
ceph-deploy --cluster=us-west mon