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diff --git a/doc/rbd/iscsi-target-ansible.rst b/doc/rbd/iscsi-target-ansible.rst new file mode 100644 index 000000000..f89c4a0d2 --- /dev/null +++ b/doc/rbd/iscsi-target-ansible.rst @@ -0,0 +1,236 @@ +========================================== +Configuring the iSCSI Target using Ansible +========================================== + +The Ceph iSCSI gateway is the iSCSI target node and also a Ceph client +node. The Ceph iSCSI gateway can be provisioned on dedicated node +or be colocated on a Ceph Object Store Disk (OSD) node. The following steps will +install and configure the Ceph iSCSI gateway for basic operation. + +**Requirements:** + +- A running Ceph Luminous (12.2.x) cluster or newer + +- Red Hat Enterprise Linux/CentOS 7.5 (or newer); Linux kernel v4.16 (or newer) + +- The ``ceph-iscsi`` package installed on all the iSCSI gateway nodes + +**Installation:** + +#. On the Ansible installer node, which could be either the administration node + or a dedicated deployment node, perform the following steps: + + #. As ``root``, install the ``ceph-ansible`` package: + + :: + + # yum install ceph-ansible + + #. Add an entry in ``/etc/ansible/hosts`` file for the gateway group: + + :: + + [iscsigws] + ceph-igw-1 + ceph-igw-2 + +.. note:: + If co-locating the iSCSI gateway with an OSD node, then add the OSD node to the + ``[iscsigws]`` section. + +**Configuration:** + +The ``ceph-ansible`` package places a file in the ``/usr/share/ceph-ansible/group_vars/`` +directory called ``iscsigws.yml.sample``. Create a copy of this sample file named +``iscsigws.yml``. Review the following Ansible variables and descriptions, +and update accordingly. See the ``iscsigws.yml.sample`` for a full list of +advanced variables. + ++--------------------------------------+--------------------------------------+ +| Variable | Meaning/Purpose | ++======================================+======================================+ +| ``seed_monitor`` | Each gateway needs access to the | +| | ceph cluster for rados and rbd | +| | calls. This means the iSCSI gateway | +| | must have an appropriate | +| | ``/etc/ceph/`` directory defined. | +| | The ``seed_monitor`` host is used to | +| | populate the iSCSI gateway’s | +| | ``/etc/ceph/`` directory. | ++--------------------------------------+--------------------------------------+ +| ``cluster_name`` | Define a custom storage cluster | +| | name. | ++--------------------------------------+--------------------------------------+ +| ``gateway_keyring`` | Define a custom keyring name. | ++--------------------------------------+--------------------------------------+ +| ``deploy_settings`` | If set to ``true``, then deploy the | +| | settings when the playbook is ran. | ++--------------------------------------+--------------------------------------+ +| ``perform_system_checks`` | This is a boolean value that checks | +| | for multipath and lvm configuration | +| | settings on each gateway. It must be | +| | set to true for at least the first | +| | run to ensure multipathd and lvm are | +| | configured properly. | ++--------------------------------------+--------------------------------------+ +| ``api_user`` | The user name for the API. The | +| | default is `admin`. | ++--------------------------------------+--------------------------------------+ +| ``api_password`` | The password for using the API. The | +| | default is `admin`. | ++--------------------------------------+--------------------------------------+ +| ``api_port`` | The TCP port number for using the | +| | API. The default is `5000`. | ++--------------------------------------+--------------------------------------+ +| ``api_secure`` | True if TLS must be used. The | +| | default is `false`. If true the user | +| | must create the necessary | +| | certificate and key files. See the | +| | gwcli man file for details. | ++--------------------------------------+--------------------------------------+ +| ``trusted_ip_list`` | A list of IPv4 or IPv6 addresses | +| | who have access to the API. By | +| | default, only the iSCSI gateway | +| | nodes have access. | ++--------------------------------------+--------------------------------------+ + +**Deployment:** + +Perform the following steps on the Ansible installer node. + +#. As ``root``, execute the Ansible playbook: + + .. prompt:: bash # + + cd /usr/share/ceph-ansible + ansible-playbook site.yml --limit iscsigws + + .. note:: + The Ansible playbook will handle RPM dependencies, setting up daemons, + and installing gwcli so it can be used to create iSCSI targets and export + RBD images as LUNs. In past versions, ``iscsigws.yml`` could define the + iSCSI target and other objects like clients, images and LUNs, but this is + no longer supported. + +#. Verify the configuration from an iSCSI gateway node: + + .. prompt:: bash # + + gwcli ls + + .. note:: + See the `Configuring the iSCSI Target using the Command Line Interface`_ + section to create gateways, LUNs, and clients using the `gwcli` tool. + + .. important:: + Attempting to use the ``targetcli`` tool to change the configuration will + cause problems including ALUA misconfiguration and path failover + issues. There is the potential to corrupt data, to have mismatched + configuration across iSCSI gateways, and to have mismatched WWN information, + leading to client multipath problems. + +**Service Management:** + +The ``ceph-iscsi`` package installs the configuration management +logic and a Systemd service called ``rbd-target-api``. When the Systemd +service is enabled, the ``rbd-target-api`` will start at boot time and +will restore the Linux IO state. The Ansible playbook disables the +target service during the deployment. Below are the outcomes of when +interacting with the ``rbd-target-api`` Systemd service. + +.. prompt:: bash # + + systemctl <start|stop|restart|reload> rbd-target-api + +- ``reload`` + + A reload request will force ``rbd-target-api`` to reread the + configuration and apply it to the current running environment. This + is normally not required, since changes are deployed in parallel from + Ansible to all iSCSI gateway nodes + +- ``stop`` + + A stop request will close the gateway’s portal interfaces, dropping + connections to clients and wipe the current LIO configuration from + the kernel. This returns the iSCSI gateway to a clean state. When + clients are disconnected, active I/O is rescheduled to the other + iSCSI gateways by the client side multipathing layer. + +**Removing the Configuration:** + +The ``ceph-ansible`` package provides an Ansible playbook to +remove the iSCSI gateway configuration and related RBD images. The +Ansible playbook is ``/usr/share/ceph-ansible/purge_gateways.yml``. When +this Ansible playbook is ran a prompted for the type of purge to +perform: + +*lio* : + +In this mode the LIO configuration is purged on all iSCSI gateways that +are defined. Disks that were created are left untouched within the Ceph +storage cluster. + +*all* : + +When ``all`` is chosen, the LIO configuration is removed together with +**all** RBD images that were defined within the iSCSI gateway +environment, other unrelated RBD images will not be removed. Ensure the +correct mode is chosen, this operation will delete data. + +.. warning:: + A purge operation is destructive action against your iSCSI gateway + environment. + +.. warning:: + A purge operation will fail, if RBD images have snapshots or clones + and are exported through the Ceph iSCSI gateway. + +.. highlight:: console + +:: + + [root@rh7-iscsi-client ceph-ansible]# ansible-playbook purge_gateways.yml + Which configuration elements should be purged? (all, lio or abort) [abort]: all + + + PLAY [Confirm removal of the iSCSI gateway configuration] ********************* + + + GATHERING FACTS *************************************************************** + ok: [localhost] + + + TASK: [Exit playbook if user aborted the purge] ******************************* + skipping: [localhost] + + + TASK: [set_fact ] ************************************************************* + ok: [localhost] + + + PLAY [Removing the gateway configuration] ************************************* + + + GATHERING FACTS *************************************************************** + ok: [ceph-igw-1] + ok: [ceph-igw-2] + + + TASK: [igw_purge | purging the gateway configuration] ************************* + changed: [ceph-igw-1] + changed: [ceph-igw-2] + + + TASK: [igw_purge | deleting configured rbd devices] *************************** + changed: [ceph-igw-1] + changed: [ceph-igw-2] + + + PLAY RECAP ******************************************************************** + ceph-igw-1 : ok=3 changed=2 unreachable=0 failed=0 + ceph-igw-2 : ok=3 changed=2 unreachable=0 failed=0 + localhost : ok=2 changed=0 unreachable=0 failed=0 + + +.. _Configuring the iSCSI Target using the Command Line Interface: ../iscsi-target-cli |