Monitor load balancer performance in a dashboard
During times of high demand on an application or service, you can configure a load balancer to help with service reliability and hardware optimization. A load balancer is a set of resources, such as servers, that absorb a large burst of HTTP, DNS, LDAP, or other types of requests.
But how well is the load balancer you designed actually working? Before a campaign launch or marketing event, how can you confirm that your load balancer won’t be a bottleneck for increased traffic? Build a dashboard!
Dashboards include multiple types of charts that reveal information about the volume of requests and traffic routed on your network, which can shed light on the effectiveness of load balancing.
This walkthrough shows you how to create a dashboard, create a device group, and then drill down on server metrics to answer the following questions:
- How much traffic is my load balancer handling?
- How well is my virtual load balancer working?
- Are back-end servers experiencing issues?
Prerequisites
- You must have access to an ExtraHop Discover appliance with a user account that has limited or full write privileges.
- You should have already configured a server-side load balancer and you will need to know the virtual IP address (VIP) on the load balancer as well as the IP addresses or name of each back-end server.
- Familiarize yourself with Dashboards concepts.
Create a dashboard
Let’s create a dashboard to display helpful visualizations about load balancer performance metrics.
How much web traffic is my load balancer handling?
Let’s monitor the number of HTTP requests that are received by your front-end virtual load balancer.
Create a device group for back-end servers
Our example load balancer consists of a single front-end virtual server and three back-end servers that host web services. To make it easier to build dashboard charts for back-end servers, we’ll first create a device group. A device group in the ExtraHop system combines all the metrics associated with several devices into one source.
How well is my load balancer working?
Let’s add a bar chart to the dashboard to see how well the front-end load balancer is distributing web requests to each back-end server.
Are back-end servers experiencing issues?
In the LB Servers HTTP Server Requests chart, we see one server handling more HTTP requests than the other servers. To understand what potential issues might be linked to the high number of requests, we’ll interact with the chart data to learn more.
Troubleshoot load balancer issues
You now have several charts to consult when a slow load balancer is reported. The following table includes suggestions for interpreting chart data and then troubleshooting issues.
Potential Issue | Look at dashboard metrics | Follow-up action |
---|---|---|
A high volume of web traffic | Review your line chart that contains the number of HTTP requests received by the front-end load balancer. Change the time interval to see how the number of requests change over time. | If you want to see which clients, URIs, referrers are associated with the highest number of requests, click the Request metric label in the chart legend. A drop-down menu appears with drill-down options. |
Traffic is not evenly distributed across back-end servers | Review the bar chart that contains a breakdown of HTTP requests received by back-end servers. Is one server receiving more requests than the others? | Not all load balancers are set up to equally balance requests. For example, a load balancer might be configured with a “sticky sessions” rules, where the distribution of requests are not perfectly identical across all servers. Follow up with your load balancer team to find out. |
Thank you for your feedback. Can we contact you to ask follow up questions?