Load balancing aids application availability and scalability. There are two load balancing options in OnApp - Load Balancer clusters and Auto-Scaling clusters. In this document you can find information on how to manage Load Balancer and Auto-Scaling clusters in your cloud.  

Load Balancers, both autoscaling clusters and load balancer clusters, can only be created on the basis of Virtual Servers and are not available for Smart Servers, Baremetal Servers, or VMware Virtual Servers.



View Load Balancers

To view the list of load balancers in your cloud go to your Control Panel's Load Balancers menu. The page that loads shows the following details of your load balancers:

  • OS - the OS on which the load balancer is based
  • Label - the name of the load balancer. Click on the label to see the load balancer details.
  • IP Addresses - IP addresses assigned to the load balancer

Note that you will be given two IP addresses. The first IP address is used by the OnApp CP to access the load balancer. The second IP address is the shared IP for the balanced nodes.

  • Disk Size - disk size assigned to the load balancer in GB
  • RAM - RAM assigned to the load balancer in GB
  • Nodes - the number of nodes in the load balancer
  • Compute Resource - the label of compute resource with which load balancer is associated
  • Power - whether the load balancer is powered ON or OFF. Click the on/off buttons to change the status.
  • Actions icon - click the icon for the quick access to the list of load balancer actions

If you are viewing the load balancers list on a narrow screen, you can customize the way the table is displayed by clicking the actions icon at the top of the table. In the drop-down list that appears, check the columns you want to be displayed and click Apply. The narrower your screen is, the more unchecked columns will be hidden from the table. If your screen is too narrow to fit all the columns you have checked, a scrollbar will appear at the bottom of the load balancers list. You can always alter your column selection later. 

Column selection is currently set for one browser. If you have checked some columns in one browser and opened the list in some other browser, the column selection will be the default one for that other browser.


View Load Balancer Details

To view load balancer details:

  1. Go to your Control Panel > Cloud > Load Balancers menu.
  2. Click the label of the load balancer you are interested in.
  3. The screen that appears loads the load balancer properties, billing statistics, and tools for managing your load balancer.

Load Balancer Overview

Load balancer properties page gives a general overview of the load balancer details:

  • Label
  • Power status & On/Off buttons
  • Compute resource 
  • Owner
  • IP addresses
  • Estimated Price per hour. This sum does not take into consideration the free limits for resources set in the bucket. Therefore, the final price for the server might differ from the sum indicated here.
  • Allocated memory
  • CPUs
  • Disk size
  • Network speed
  • IPs
  • Hostname and login
  • Administrator's/user's notes
  • List of cluster nodes
  • Activity log

Add admin's or user's note to create a brief comment or reminder.

To expand the load balancer options menu, click the Actions button on the load balancer's details screen. Actions menu enables you to perform the following actions on load balancers (the exact list shown depends on the load balancer status):

Actions

The exact list of load balancer tools shown depends on the load balancer status:

Power Options:

  • Startup Balancer - queues a start-up action for a balancer that's currently powered off
  • Reboot Balancer - powers off and then restarts the balancer
  • Shut Down Balancer - terminates the balancer forcefully
  • Suspend Balancer - stops a balancer and changes its status to suspended

Options:

  • Rebuild Balancer - pops up the balancer rebuild dialogue, where you can rebuild the balancer on the same (or another) template. After rebuild all data will be lost.
  • Edit Balancer - redirects to the edit load balancer details page
  • Migrate Balancer - pops up the balancer migration dialogue, enabling you to move the balancer to a different compute resource
  • Delete Balancer - removes the balancer from the system

Network:

  • Network Interfaces - redirects to the network interfaces page 

Cluster Nodes:

This is the list of the nodes which form the load balancer. Here you can:

  • Power on/off the node.
  • Delete a node from a cluster.

To view load balancer's billing statistics or autoscaling monitors, click the appropriate tab.


View Load Balancer Billing Statistics

To view billing statistics for a load balancer:

  1. Go to your Control Panel > Cloud > Load Balancers menu.
  2. Click the label of the balancer you're interested in.
  3. Click the Billing Stats tab.
  4. You can filter the statistics by date and time - select the time period from the drop-down menu and click the Apply button. By default the statistics are generated for the last three months or the actual VS existence period.
  5. Move the Show in my Timezone slider to the right if you want to show bandwidth statistics according to your profile's timezone settings.
  6. On the page that appears:

    The price parameters on this page do not take into consideration the free limits for resources set in the bucket.

    • Date – particular date and time for the generated statistics
    • Users – the load balancer owner. Click the owner name to see the User Profile (user details)
    • Virtual Servers – the virtual server name with the total due for LB resources (CPU priority, CPUs, memory and template resources) for the point of time specified in the Date column.
    • Network Interfaces Usage – the total due for the network interfaces used by this LB for the point of time specified in the Date column. Click the network interface name to see its details.
    • Disks Usage – the list of disks assigned to this LB with the total due for the disk space resources (disk size, data read/written, reads/writes completed) for the point of time specified in the Date column. Click the disk name to see its details.
    • Costs – the total due for the Virtual Servers, Network Interfaces and Disks resources at the point of time specified in the Date column.

Scroll down to see Total Amount (the total due for the whole billing statistics period).


View Load Balancer Autoscaling Monitors

Autoscaling monitors provide information about the cluster load.

To view the load balancer's autoscaling monitors:

  1. Go to your Control Panel > Cloud > Load Balancers menu.
  2. Click the label of the balancer you're interested in.
  3. Click the Autoscaling Monitors tab.
  4. On the screen that appears, you will see the list of autoscaling monitors along with the following details:
  • monitor name
  • virtual server label

Click the label of a monitor you are interested in to view its details:

Depending on the monitor type, the monitor details screen page will show the the following info:

Memory Monitor

Memory Monitor Info:

  • Name of the memory test - test label
  • IP of the device agent - IP address of the agent running on the server
  • Platform - OS platform
  • The name of the agent - virtual server identifier
  • Free memory limit - free memory limit in MB
  • Free swap limit - free swap limit in MB

Memory Last Results:

  • Free memory - free virtual server memory in MB
  • Total memory - total virtual server memory in MB
  • Free swap - free swap disk size in MB
  • Total swap (MB)
  • Buffered memory (MB)
  • Cached memory (MB)
  • Status - monitor status: OK, if the monitor is correct or NOK, if the autoscaling configuration does not match. Monitor status is refreshed once in 5 minutes.

CPU Monitor

CPU Monitor Info

Name of the CPU test - CPU test label

IP of the device agent - virtual server IP address

Max value for kernel - maximum CPU value for kernel

Max value for iowait - maximum CPU value for iowait

Platform - virtual server OS

Max allowed value for user - maximum CPU value for user processes

The name of the agent - virtual server identifier

Tag of the CPU test - CPU test tag

Min allowed value for idle - minimum CPU value for idle mode

Max allowed value for nice - maximum CPU value for nice

Max value is a CPU priority set during the server creation.

CPU Last Results

CPU index - CPU number

User Value - percentage of CPU used in user mode

Kernel Value - percentage of CPU used by kernel

Nice Value -  percentage of CPU time occupied by processes with positive CPU value

Idle Value - percentage of CPU used in idle mode

IO Wait Value - percentage of time the CPU was idle during the IO request

Status - monitor status: OK, if the monitor is correct or NOK, if the autoscaling configuration does not match. Monitor status is refreshed once in 5 minutes.


Edit Load Balancer

To edit a load balancer:

  1. Go to your Control Panel > Cloud > Load Balancers menu.
  2. Click the Actions icon next to a required load balancer, then choose Edit Cluster.
  3. When the page loads, edit necessary parameters and click Save.
When you increase the RAM of the nodes of a load balancer (autoscaling type) to a value greater than the current node RAMx16 (which is a max_mem parameter in a configuration file and database), the load balancer will be cold resized.
When deleting load balancer ports, you can remove all but the first port.

Delete Load Balancer

To delete a load balancer:

  1. Go to your Control Panel > Cloud > Load Balancers menu.
  2. Click the Delete icon next to a required load balancer.
  3. Click OK to confirm the deletion.


Troubleshooting

If your load balancer is not working, please check the following parameters:

  • Are the VSs online?
  • Are the VSs on the same subnet?
  • Is traffic between the LB and VS restricted? Check the firewall rules on the VSs by visiting Control Panel > Cloud > Virtual Servers menu label of the virtual server Networking tab > Firewall. The load balancer will not work if it cannot communicate with each VS.

Please note that the load balancer has two IP addresses. The first one is for the CP server to connect and manage the LB, and the other one is for the web traffic.


See also:

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