91 lines
3.3 KiB
Markdown
91 lines
3.3 KiB
Markdown
[[!meta title="How to access gluster from multiple networks"]]
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# TL;DR
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Create volumes name based instead of IP based:
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gluster volume create xfs-plain replica 2 transport vmhost1:/home/gluster vmhost2:/home/gluster
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instead of
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gluster volume create xfs-plain replica 2 transport 192.168.0.1:/home/gluster 192.168.0.2:/home/gluster
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And have the names point to different IP addresses.
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## The setup
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The basic setup (in our case) looks like this:
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---------------------------------
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| Clients / Users |
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---------------------------------
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--------------------------------- ---------------------------------
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| frontend (with opennebula) | ---| vmhost1 with glusterfs |
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--------------------------------- / ---------------------------------
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| / eth0 eth1
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|-------------------------< ||
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\ eth0 eth1
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\ ---------------------------------
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---| vmhost2 with glusterfs |
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---------------------------------
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The frontend running [[!opennebula]] connects to
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**vmhost1** and **vmhost2** using their public interfaces.
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The gluster bricks running on the vm hosts are supposed to communicate
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via eth1, so that the traffic for [[!gluster]] does not influence
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the traffic of the virtual machines to the Internet. The gluster filesystem
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of the vmhosts is only thought to be used by the virtual machines running
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on those two hosts - an isolated cluster. Thus the volume initially has been created
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like this:
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gluster volume create xfs-plain replica 2 transport 192.168.0.1:/home/gluster 192.168.0.2:/home/gluster
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## The problem
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However, the frontend requires access to the gluster volume, because
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[[!opennebula]] needs to copy and import the VM image into the gluster
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datastore. Even though the *glusterd* process listens on any IP address,
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the volume contains the information that it runs on 192.168.0.1
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and 192.168.0.2 and is thus not reachable from the frontend.
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## Using name based volumes
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The frontend can reach the vm hosts via **vmhost1** and **vmhost2**,
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which resolves to their **public IP addresses** via DNS.
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On the vm hosts we created entries in **/etc/hosts** using [[!cdist]]
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that looks as following:
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192.168.0.1 vmhost1
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192.168.0.2 vmhost2
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Now we re-created the volume using
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gluster volume create xfs-plain replica 2 transport tcp vmhost1:/home/gluster vmhost2:/home/gluster
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gluster volume start xfs-plain
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And it correctly shows up in the volume info:
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%gluster volume info
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Volume Name: xfs-plain
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Type: Replicate
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Volume ID: fe45c626-c79d-4e67-8f19-77938470f2cf
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Status: Started
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Number of Bricks: 1 x 2 = 2
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Transport-type: tcp
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Bricks:
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Brick1: vmhost1-cluster1.place4.ungleich.ch:/home/gluster
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Brick2: vmhost2-cluster1.place4.ungleich.ch:/home/gluster
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And now we can mount it successfully on the frontend using
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% mount -t glusterfs vmhost2:/xfs-plain /mnt/gluster
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[[!inline pages="follow-up-include" archive="no" show=0 raw=yes]]
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[[!tag gluster filesystem unix ungleich]]
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