How to configure High Availability (HA) on RackSpace in ScaleArc

Release Document Status DB Platform Categories
3.8 or higher INFO All High Availibility

 

QUESTION

How to configure High Availability (HA) on RackSpace in Scalearc?

 

ANSWER

High Availability (HA) allows a pair of ScaleArc servers to function as a redundant cluster. This KB describes the steps to configure High Availability cluster pair in ScaleArc on RackSpace.

 

Pre-Requisites to configure HA on RackSpace:

Create two scalearc v3.8 or later instance in RackSpace which are:

  • Both instances must be reachable to each other
  • Their ScaleArc configuraiton must be identical in terms of:
    • Flavor Type (i.e. 4 GB General Purpose v1)
    • ScaleArc release version (i.e. ScaleArc v3.8.4)
    • ScaleArc License (Cores, Cluster size, Cache Size)
    • Replace idbha1 with actual Hostname of the machine on both instances in following configuration files.
    Ha.cf present at location /etc/ha.d/ha.cf


     

 

          Haresources present at /etc/ha.d/haresources

          

 

  • Create a Loadbalancer under Network Tab of RackSpace. This loadbalancer Network IP will acts as virtual IP to which application is interacting.

        

 

              Health Monitoring should be enabled to configure HA so that Loadbalancer detect the Nodes status every 10 seconds.

 

 

After enabling Health Monitoirng, You will find one Node condition as enable and other as Automatically disabled.

Configure HA on RackSpace

  1. Enable SSH
    If you are unable to see the HA Settings in the Settings tab. To see the HA setting tab we need to access the Scalearc server using SSH.
    Please refer this link to enable SSH access using UI.

  2. Modify instance type
    Once we login to scalearc server using SSH, use the following command on both the scalearc servers :

    # echo 2 > /system/iscloud.txt
  3. Modify HEARTBEAT parameters
    Go to Settings in Scalearc UI and check if the HA settings are visible.


    Go to Settings >> HA settings:


    Click on Configure and change the Keep Alive and DeadTime parameters.
    Please refer this link for recommended configuration on virtual environment.

    -> KeepAlive(ms): 1000ms
    -> DeadTime(Sec): 5 sec
    -> WarnTime(ms): 2500ms(*automatically set*)



  4. Configure HA
    On the Primary Scalearc Node Go to Settings >> HA settings
    Enter Remote Interface (Interface of the Secondary Node) and Remote IP (Internal IP of the Secondary Node).

          Click on “Add as Secondary” and enter the UI credentials of the Secondary Scalearc Instance.    

                                                                                            

A confirmation message is seen once HA configuration is completed.

We can check the HA Configuration under Settings >> HA settings.

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