RedLine13 makes it easy to scale your load tests in the cloud, but sometimes there are a few moving parts to coordinate. While it can be disappointing when a test fails to start, in most cases there are only a few common reasons preventing such a “grounded” test from launching. In this article, we will walk through some of these common scenarios. In each of these cases we will discuss troubleshooting steps and potential solutions.
Network Configuration Issues
One of the most common causes facing a test which fails to start can be traced to network configuration issues. RedLine13 interfaces with your AWS account, automating the process of provisioning load generator servers and running your test. Following the step-by-step guide in our documentation can help avoid certain pitfalls in initial configuration that prevent load tests from launching. Some of the most common reasons for network configuration issues include the following:
- Issues with IAM policy configuration
- Missing Internet Gateway on VPC
- Incorrect or missing subnet mapping
- Security group rule configuration
- Using an outdated key pair
AWS Account Issues
For most tests of modest size, service quotas usually are not a relevant constraint. However, if your load test requires a particularly high vCPU count your test may fail to start due to your AWS account not having permission to spin up enough instances. Factors which make you more likely to hit this limit include:
- Requesting large numbers of load generator servers
- Using many very large sized EC2 instances
- Utilizing specialized or uncommon EC2 instance types
- Newly created AWS accounts have lower initial service quota limits
Configuration Issues
This is a broad category where virtually an infinite number of configuration reasons can cause a test to fail on startup. However, some of the more common issues include:
- Required dependencies are missing (e.g., a required
JARclass) - Misconfigured JMeter/JVM command line parameters
- Invalid references to non-included JMeter classes
Performance Issues
Any of the above situations can cause a load test to fail before it can even be started. While performance issues can manifest at any point during the execution of your test, encountering severe performance issues at the outset can cause test telemetry to fail and therefore present similarly. Some strategies to prevent performance issues from limiting your tests include:
- Know how to scale your load test with size and number of load generator servers
- Optimize your JMeter scripting for both memory and CPU performance
- Keep average CPU usage below 100% and ideally <80% at all times
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