挂载 CephFS ：先决条件

You can use CephFS by mounting it to your local filesystem or by using cephfs-shell. CephFS can be mounted using kernel as well as using FUSE. Both have their own advantages. Read the following section to understand more about both of these ways to mount CephFS.

用哪个 CephFS 客户端？

FUSE 客户端是最简便、也最容易升级到与存储集群一致的 Ceph 版本，但是内核客户端的性能通常更好。

遇到缺陷或性能问题时，最好试试另一个客户端，以甄别此缺陷是否特定于客户端（然后报告给开发者）。

General Pre-requisite for Mounting CephFS

Before mounting CephFS, ensure that the client host (where CephFS has to be mounted and used) has a copy of the Ceph configuration file (i.e. ceph.conf) and a keyring of the CephX user that has permission to access the MDS. Both of these files must already be present on the host where the Ceph MON resides.

  1. Generate a minimal conf file for the client host and place it at a standard location:

    # on client host
mkdir -p -m 755 /etc/ceph
ssh {user}@{mon-host} "sudo ceph config generate-minimal-conf" | sudo tee /etc/ceph/ceph.conf

    Alternatively, you may copy the conf file. But the above method generates a conf with minimal details which is usually sufficient. For more information, see Client Authentication and 自举引导选项.

  2. Ensure that the conf has appropriate permissions:

    chmod 644 /etc/ceph/ceph.conf

  3. Create a CephX user and get its secret key:

    ssh {user}@{mon-host} "sudo ceph fs authorize cephfs client.foo / rw" | sudo tee /etc/ceph/ceph.client.foo.keyring

    In above command, replace cephfs with the name of your CephFS, foo by the name you want for your CephX user and / by the path within your CephFS for which you want to allow access to the client host and rw stands for both read and write permissions. Alternatively, you may copy the Ceph keyring from the MON host to client host at /etc/ceph but creating a keyring specific to the client host is better. While creating a CephX keyring/client, using same client name across multiple machines is perfectly fine.

    Note

    If you get 2 prompts for password while running above any of 2 above command, run sudo ls (or any other trivial command with sudo) immediately before these commands.

  4. Ensure that the keyring has appropriate permissions:

    chmod 600 /etc/ceph/ceph.client.foo.keyring

Note

There might be few more prerequisites for kernel and FUSE mounts individually, please check respective mount documents.