Read More

High Availability Config

Table of Contents

Replication

Server Address | Replication Cluster | Heart Beat Interval (secs) | Heart Beat Timeout (secs) | Is Gzip Stream | Max Sequence Number Difference | Sync Interval | Data Master Priority | Enable Replication for Cached Data | File Cache Server Address

HA Virtual Interface Configuration

Name | Virtual IPs | Virtual IP ID | Virtual IP Token | NIC Name | Priority | Internal Device | Unicast Source Virtual IP | Unicast Peer Virtual IPs

HA Status

Replication Status

Server Address

Description

Local IP address and port used for replication.

Syntax

IP:port

Replication Cluster

Description

List of replicators, by their IP Address and port number, that are a part of this replication cluster.

Syntax

Comma separated list in the form IP:port

Heart Beat Interval (secs)

Description

The time interval that "I am alive" messages will be sent.

Syntax

Integer number

Heart Beat Timeout (secs)

Description

The time interval after which, if "I am alive" message is not sent, the replicator will be considered to have failed. Must be set higher than Heart Beat interval (secs).

Syntax

Integer number

Is Gzip Stream

Description

Enable Gzip compression for replicator traffic.

Syntax

Select from radio box

Max Sequence Number Difference

Description

Compares to the difference between the last sequence number sent and the last sequence number acknowledged by the master. If the difference is larger than maxAckDiff, individual SHM updates are paused until the next bulk update is complete.

This difference indicates the busy-ness level of the master. If multiple nodes are syncing a significant amount of data with the master, this value ensures that the data sync is still manageable and performs at an optimal level.

Default value: 100

Syntax

Number between 1 and 65535.

Sync Interval

Description

The time in seconds that a node will remain in the upgrading state before transitioning to master. This interval is used to allow the group to communicate with one another to ensure that the correct node is selected as master. It is strongly recommended that this is set to a longer interval than the Heart Beat Interval.

Default value: 30

Syntax

Number between 1 and 255.

Data Master Priority

Description

Indicates the *data sync priority*. The node with the highest priority is selected to be the data sync 'master', when there are no masters selected yet. If a master is already selected, that node will remain master. Note that this is for data sync ONLY. The priority value in the HA Interfaces configuration group is for Virtual IP priority.

Default value: 0

Syntax

Number between -32766 and 32767.

Enable Replication for Cached Data

Description

Enable file cache replication.

Syntax

Select from radio box

File Cache Server Address

Description

Select file cache server address.

Syntax

IP:port

HA Virtual Interface Configuration

Description

Additions/Deletions/Changes made will not take effect until applied through HA -> Status page.

Name

Description

A unique number that identifies a virtual interface.

Syntax

Integer number

Virtual IPs

Description

A list of virtual IP addresses used to access the HA interface. These addresses can be either an IPv4 or IPv6 and must be on the same subnet as the real IP address.

Please verify proper usage with keepalived prior to using multiple Virtual IPs.

Syntax

comma separated list

Virtual IP ID

Description

The ID of the virtual IP address. Please use an integer number between 1 and 10. Virtual IP, Virtual IP ID, and Virtual IP Token must be the same for the same HA group.

Virtual IP Token

Description

A virtual IP address token is required to authenticate interface(carp/vrrp) advertisements. Virtual IP, Virtual IP ID, and Virtual IP Token must be same for the same HA group.

NIC Name

Description

The NIC name (such as eth0, eth1, etc..) that the virtual IP will bind to. Required for Linux platforms.

Note: Even though it is required, this setting will have no effect on FreeBSD platforms.

Priority

Description

The priority for this load balancer server, where a higher number equals a higher priority. The highest priority load balancer will act as the master, with the others in the cluster acting as slaves.

Note: This is reversed for FreeBSD platforms where a lower number equals a higher priority.

Syntax

Integer number

Internal Device

Description

The Internal Device (such as eth0, eth1, etc..) to use for internal communication by unicast/multicast. If this is different than the NIC Name configuration, the Keepalived configuration will be adjusted accordingly.

Default value: Configured NIC Name value

Syntax

Select from drop down list

Unicast Source Virtual IP

Description

The local machine's virtual IP used to send Unicast messages.

Unicast Peer Virtual IPs must also be set for Unicast to be used. (Multicast is used by default)

Tips

Unicast is generally slower and more resource intensive than Multicast.

Unicast Peer Virtual IPs

Description

List of peer virtual IPs to send Unicast messages to. There should be one peer IP entry for each node expected to handle request processing.

Unicast Source Virtual IP must also be set for Unicast to be used. (Multicast is used by default)

Syntax

comma separated list

Tips

Unicast is generally slower and more resource intensive than Multicast.

HA Status

Description

Displays the configuration and status of currently configured/live high availability interfaces by their unique Interface ID. The current configured settings for each interface are shown as well as the actual "live" settings in green. The "Status" field will contain 1-2 of the following values:

  • Newly Configured: The interface is configured but has not yet been created. Click "Add" to create this interface.
  • Not in Config File: There is currently no interface configuration with a matching Interface ID for this interface. You can click "Delete" to delete this interface.
  • Matched: The current configuration settings for this Interface ID match the configuration settings of the corresponding live interface.
  • Not match with System: The current configuration settings for this Interface ID do not match the configuration settings of the corresponding live interface. Click "Apply Changes" to overwrite the live settings with the configured settings.
  • master: Indicates that this interface has the role of master.
  • standby: Indicates that this interface has the role of slave.

Tips

Configuration changes made to a high availability interface in the config section will not be applied until clicking "Apply Changes" next to the affected interface. The same applies to adding new interfaces and deleting existing interfaces, changes will not be applied until clicking "Add/Delete" respectively.

Replication Status

Description

Displays the status of currently "live" replicators in the replication cluster by their server addresses, as well as the number of active sessions on record for each replicator. The source replicator (usually the first to come online) will have a highlighted SRC tag in front of it's Server Address. It is this replicators job to actively sync it's data to the other replicators in the replication cluster. These other replicators will be compared against the source replicator to determine if they are "in Sync" or "out of Sync".

SSL Session will show the number of currently cached SSL sessions for the current load balancer.

ID Session will show the session count in the session cache of each cluster defined in the load balancer.

Replication will happen in real-time as changes are written to shared memory.