Move all virtual machines from the node. Make sure you have no local
data or backups you want to keep, or save them accordingly.
+In the following example we will remove the node hp4 from the cluster.
-Log in to one remaining node via ssh. Issue a `pvecm nodes` command to
-identify the node ID:
-
-----
-hp1# pvecm status
-
-Quorum information
-~~~~~~~~~~~~~~~~~~
-Date: Mon Apr 20 12:30:13 2015
-Quorum provider: corosync_votequorum
-Nodes: 4
-Node ID: 0x00000001
-Ring ID: 1928
-Quorate: Yes
-
-Votequorum information
-~~~~~~~~~~~~~~~~~~~~~~
-Expected votes: 4
-Highest expected: 4
-Total votes: 4
-Quorum: 2
-Flags: Quorate
-
-Membership information
-~~~~~~~~~~~~~~~~~~~~~~
- Nodeid Votes Name
-0x00000001 1 192.168.15.91 (local)
-0x00000002 1 192.168.15.92
-0x00000003 1 192.168.15.93
-0x00000004 1 192.168.15.94
-----
-
-IMPORTANT: at this point you must power off the node to be removed and
-make sure that it will not power on again (in the network) as it
-is.
+Log in to a *different* cluster node (not hp4), and issue a `pvecm nodes`
+command to identify the node ID to remove:
----
hp1# pvecm nodes
4 1 hp4
----
-Log in to one remaining node via ssh. Issue the delete command (here
-deleting node `hp4`):
+
+At this point you must power off hp4 and
+make sure that it will not power on again (in the network) as it
+is.
+
+IMPORTANT: As said above, it is critical to power off the node
+*before* removal, and make sure that it will *never* power on again
+(in the existing cluster network) as it is.
+If you power on the node as it is, your cluster will be screwed up and
+it could be difficult to restore a clean cluster state.
+
+After powering off the node hp4, we can safely remove it from the cluster.
hp1# pvecm delnode hp4
0x00000003 1 192.168.15.92
----
-IMPORTANT: as said above, it is very important to power off the node
-*before* removal, and make sure that it will *never* power on again
-(in the existing cluster network) as it is.
-
-If you power on the node as it is, your cluster will be screwed up and
-it could be difficult to restore a clean cluster state.
-
If, for whatever reason, you want that this server joins the same
cluster again, you have to
it is likely that some nodes boots faster than others. Please keep in
mind that guest startup is delayed until you reach quorum.
+
Guest Migration
---------------
-Migrating Virtual Guests (live) to other nodes is a useful feature in a
-cluster. There exist settings to control the behavior of such migrations.
-This can be done cluster wide via the 'datacenter.cfg' configuration file or
-also for a single migration through API or command line tool parameters.
+Migrating virtual guests to other nodes is a useful feature in a
+cluster. There are settings to control the behavior of such
+migrations. This can be done via the configuration file
+`datacenter.cfg` or for a specific migration via API or command line
+parameters.
+
Migration Type
~~~~~~~~~~~~~~
The migration type defines if the migration data should be sent over a
-encrypted ('secure') channel or an unencrypted ('insecure') one.
+encrypted (`secure`) channel or an unencrypted (`insecure`) one.
Setting the migration type to insecure means that the RAM content of a
-Virtual Guest gets also transfered unencrypted, which can lead to
-information disclosure of critical data from inside the guest for example
-passwords or encryption keys.
-Thus we strongly recommend to use the secure channel if you have not full
-control over the network and cannot guarantee that no one is eavesdropping
-on it.
+virtual guest gets also transfered unencrypted, which can lead to
+information disclosure of critical data from inside the guest (for
+example passwords or encryption keys).
-Note that storage migration do not obey this setting, they will always send
-the content over an secure channel currently.
+Therefore, we strongly recommend using the secure channel if you do
+not have full control over the network and can not guarantee that no
+one is eavesdropping to it.
+
+NOTE: Storage migration does not follow this setting. Currently, it
+always sends the storage content over a secure channel.
+
+Encryption requires a lot of computing power, so this setting is often
+changed to "unsafe" to achieve better performance. The impact on
+modern systems is lower because they implement AES encryption in
+hardware. The performance impact is particularly evident in fast
+networks where you can transfer 10 Gbps or more.
-While this setting is often changed to 'insecure' in favor of gaining better
-performance on migrations it may actually have an small impact on systems
-with AES encryption hardware support in the CPU. This impact can get bigger
-if the network link can transmit 10Gbps or more.
Migration Network
~~~~~~~~~~~~~~~~~
-By default {pve} uses the network where the cluster communication happens
-for sending the migration traffic. This is may be suboptimal, for one the
-sensible cluster traffic can be disturbed and on the other hand it may not
-have the best bandwidth available from all network interfaces on the node.
-Setting the migration network parameter allows using a dedicated network for
-sending all the migration traffic when migrating a guest system. This
-includes the traffic for offline storage migrations.
-
-The migration network is represented as a network in 'CIDR' notation. This
-has the advantage that you do not need to set a IP for each node, {pve} is
-able to figure out the real address from the given CIDR denoted network and
-the networks configured on the target node.
-To let this work the network must be specific enough, i.e. each node must
-have one and only one IP configured in the given network.
+By default, {pve} uses the network in which cluster communication
+takes place to send the migration traffic. This is not optimal because
+sensitive cluster traffic can be disrupted and this network may not
+have the best bandwidth available on the node.
+
+Setting the migration network parameter allows the use of a dedicated
+network for the entire migration traffic. In addition to the memory,
+this also affects the storage traffic for offline migrations.
+
+The migration network is set as a network in the CIDR notation. This
+has the advantage that you do not have to set individual IP addresses
+for each node. {pve} can determine the real address on the
+destination node from the network specified in the CIDR form. To
+enable this, the network must be specified so that each node has one,
+but only one IP in the respective network.
+
Example
^^^^^^^
-Lets assume that we have a three node setup with three networks, one for the
-public communication with the Internet, one for the cluster communication
-and one very fast one, which we want to use as an dedicated migration
-network. A network configuration for such a setup could look like:
+We assume that we have a three-node setup with three separate
+networks. One for public communication with the Internet, one for
+cluster communication and a very fast one, which we want to use as a
+dedicated network for migration.
+
+A network configuration for such a setup might look as follows:
----
iface eth0 inet manual
iface eth2 inet static
address 10.1.2.1
netmask 255.255.255.0
-
-# [...]
----
-Here we want to use the 10.1.2.1/24 network as migration network.
-For a single migration you can achieve this by using the 'migration_network'
-parameter:
+Here, we will use the network 10.1.2.0/24 as a migration network. For
+a single migration, you can do this using the `migration_network`
+parameter of the command line tool:
+
----
-# qm migrate 106 tre --online --migration_network 10.1.2.1/24
+# qm migrate 106 tre --online --migration_network 10.1.2.0/24
----
-To set this up as default network for all migrations cluster wide you can use
-the migration property in '/etc/pve/datacenter.cfg':
+To configure this as the default network for all migrations in the
+cluster, set the `migration` property of the `/etc/pve/datacenter.cfg`
+file:
+
----
-# [...]
-migration: secure,network=10.1.2.1/24
+# use dedicated migration network
+migration: secure,network=10.1.2.0/24
----
-Note that the migration type must be always set if the network gets set.
+NOTE: The migration type must always be set when the migration network
+gets set in `/etc/pve/datacenter.cfg`.
+
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include::pve-copyright.adoc[]
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