10.3. Preparing to Deploy Geo-replication

1. Verify that your environment matches the minimum system requirements. See Section 10.3.3, “Prerequisites”.
2. Determine the appropriate deployment scenario. See Section 10.3.1, “Exploring Geo-replication Deployment Scenarios”.
3. Start geo-replication on the master and slave systems. See Section 10.4, “Starting Geo-replication”.

Creating Geo-replication Sessions

1. To create a common pem pub file, run the following command on the master node where the password-less SSH connection is configured:

   # gluster system:: execute gsec_create

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2. Create the geo-replication session using the following command. The push-pem option is needed to perform the necessary pem-file setup on the slave nodes.

   # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL create push-pem [force]

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   For example:

   # gluster volume geo-replication master-vol example.com::slave-vol create push-pem

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   Note

   There must be password-less SSH access between the node from which this command is run, and the slave host specified in the above command. This command performs the slave verification, which includes checking for a valid slave URL, valid slave volume, and available space on the slave. If the verification fails, you can use the force option which will ignore the failed verification and create a geo-replication session.
3. Verify the status of the created session by running the following command:

   # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL status

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1. Create a new group. For example, geogroup.
2. Create a unprivileged account. For example, geoaccount. Add geoaccount as a member of geogroup group.
3. As a root, create a new directory with permissions 0711. Ensure that the location where this directory is created is writeable only by root but geoaccount is able to access it. For example, create a mountbroker-root directory at /var/mountbroker-root.
4. Add the following options to the glusterd.vol file, assuming the name of the slave Red Hat Storage volume as slavevol:

   option mountbroker-root /var/mountbroker-root
   option mountbroker-geo-replication.geoaccount slavevol
   option geo-replication-log-group geogroup 
   option rpc-auth-allow-insecure on

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   See Section 2.4, “Storage Concepts” for information on volume file of a Red Hat Storage volume.
   If you are unable to locate the glusterd.vol file at /etc/glusterfs/ directory, create a vol file containing both the default configuration and the above options and save it at /etc/glusterfs/.
   The following is the sample glusterd.vol file along with default options:

   volume management
       type mgmt/glusterd
       option working-directory /var/lib/glusterd
       option transport-type socket,rdma
       option transport.socket.keepalive-time 10
       option transport.socket.keepalive-interval 2
       option transport.socket.read-fail-log off
       option rpc-auth-allow-insecure on
       
       option mountbroker-root /var/mountbroker-root 
       option mountbroker-geo-replication.geoaccount slavevol
       option geo-replication-log-group geogroup
   end-volume

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   • If you have multiple slave volumes on Slave, repeat Step 2 for each of them and add the following options to the vol file:

     option mountbroker-geo-replication.geoaccount2 slavevol2
     option mountbroker-geo-replication.geoaccount3 slavevol3

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   • You can add multiple slave volumes within the same account (geoaccount) by providing comma-separated list (without spaces) as the argument of mountbroker-geo-replication.geogroup. You can also have multiple options of the form mountbroker-geo-replication.*. It is recommended to use one service account per Master machine. For example, if there are multiple slave volumes on Slave for the master machines Master1, Master2, and Master3, then create a dedicated service user on Slave for them by repeating Step 2. for each (like geogroup1, geogroup2, and geogroup3), and then add the following corresponding options to the volfile:

     option mountbroker-geo-replication.geoaccount1 slavevol11,slavevol12,slavevol13
     option mountbroker-geo-replication.geoaccount2 slavevol21,slavevol22
     option mountbroker-geo-replication.geoaccount3 slavevol31

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5. Restart glusterd service on all the Slave nodes.
   After you setup an auxiliary glusterFS mount for the unprivileged account on all the Slave nodes, perform the following steps to setup a non-root geo-replication session.:
6. Setup a passwdless SSH from one of the master node to the user on one of the slave node. For example, to geoaccount.
7. Create a common pem pub file by running the following command on the master node where the password-less SSH connection is configured to the user on the slave node:

   # gluster system:: execute gsec_create

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8. Create a geo-replication relationship between master and slave to the user by running the following command on the master node:
   For example,

   # gluster volume geo-replication MASTERVOL geoaccount@SLAVENODE::slavevol create push-pem

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   If you have multiple slave volumes and/or multiple accounts, create a geo-replication session with that particular user and volume.
   For example,

   # gluster volume geo-replication MASTERVOL geoaccount2@SLAVENODE::slavevol2 create push-pem

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9. In the slavenode, which is used to create relationship, run /usr/libexec/glusterfs/set_geo_rep_pem_keys.sh as a root with user name, master volume name, and slave volume names as the arguments.
   For example,

    # /usr/libexec/glusterfs/set_geo_rep_pem_keys.sh geoaccount MASTERVOL SLAVEVOL_NAME 

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10. Start the geo-replication with slave user by running the following command on the master node:
    For example,

    # gluster volume geo-replication MASTERVOL geoaccount@SLAVENODE::slavevol start

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11. Verify the status of geo-replication session by running the following command on the master node:

    # gluster volume geo-replication MASTERVOL geoaccount@SLAVENODE::slavevol status

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