Kubernetes (K8s) is already considered the de facto standard for container orchestration. After six years since its introduction, it has reached a level of popularity that developers can no longer ignore. However, many continue to be intimidated by this relatively new technology. One of the challenges of working with K8s is troubleshooting errors, because of how complex the infrastructure is. It is also relatively new, so it would take some time for most developers to gain familiarity.
Still, there is no reason to dread using Kubernetes. In the words of Matt Asay, former Amazon Web Services Principal and Adobe Head of Developer Ecosystem, “Kubernetes is so hard, but worth the pain.” It is totally learnable and remotely the daunting enigma many think it is, as demonstrated by the error troubleshooting below.
Getting to Know Exit Code 1
Exit code 1 is one of the common errors encountered in using Kubernetes. It happens when a container is terminated usually because of a failure in an application. It can also occur because of an invalid reference, wherein a file reference for an image used to operate the container does not exist or points to an incompatible object.
Sounds plain and straightforward? Not exactly. Part of knowing this error is also getting acquainted with SIGHUP or Signal 7. When an app terminates and shows Exit Code 1, there is a corresponding signal from the operating system called Signal 7.
This is just a simple illustration of the kind of dynamic developers have to deal with as they troubleshoot Kubernetes. The platform and the problems in it cannot be dealt with in isolation. It will be necessary to become familiar with interlinked systems. It is also important to memorize or be familiar with the different exit codes, as they provide important hints in diagnosing issues with pods.
Anyway, Exit Code 1 is not shown as is in the command line interface (CLI). If a container exits, the CLI shows the line “Exited (1)” – wherein the number enclosed in parentheses is the exit code.
Diagnosing Exit Code 1
To start diagnosing the error, the first step is to list all the containers that exited with an error code. In Docker, the command to use is “ps -la”. With Kubernetes, the command is “kubectl describe pod [POD_NAME]”.
After finding the affected containers, the next step is to examine the container engine logs to see if the error is attributable to an invalid reference, as evidenced by a “not found” file for the image specification. If the issue is not because of an invalid reference, the next step is to locate the library within the container that caused the error. The debugging of the problematic library follows.
Troubleshooting – Standard DIY Process
There are a number of approaches in troubleshooting an Exit Code 1 error, as described below.
# Container deletion and recreation – This approach is like a factory reset, allowing developers to start with a fresh clean slate. All temporary files and transient conditions, including those that are the possible causes of the error, are removed and then recreated mindfully to make sure that they no longer have issues in them.
# App troubleshooting through container bashing – This technique is applicable in cases where containers do not use entry points and there is reasonable suspicion that the Exit Code 1 issue is brought about by an application. Bashing entails the use of the bashing command (bash) to run in a shell within the container to run the app that is suspected to be causing the problem and check if it exits and returns the Exit Code 1 error.
# App troubleshooting without bashing – It is also possible to identify and troubleshoot the issue that could be related to the app by running the app outside the container. However, for this to work, it is crucial that the new environment with which the application is made to run should be similar to that of the previous container where the suspected app is (possibly) causing an error.
# App parameters experimentation – It is also possible to find and troubleshoot app-related difficulties that cause the Exit Code 1 error by trying different configurations of the app. This is a trial-and-error strategy, so tons of patience would be needed. Some of the app configurations that can be modified are the memory allocation, the toggling of special switches or flags, changing of the ports used to connect to the relevant network, and the modification of environment variables.
# Resolving the PID 1 problem – There are instances where the Exit Code 1 error results from a PID 1 problem or the init process that generates other processes and causes the transmission of signals. This happens when the PID is indicated as “1” when running the “ps -aux” command. Resolving the PID 1 problem is possible by forcing a container that refuses to start using tools like dumb-init. In Kubernetes, it can be addressed by running the container through Share Process Namespace (PID 5). In Docker, the possible solution is to add the init parameter to “docker-compose.yml”.
Troubleshooting with an Automated Solution
Exit Code 1 can be a challenging error, as it is difficult to identify the specific cause. The issue can be attributed to various concerns that are known to create the same errors. Inexperienced developers can expect to have a hard time overcoming the confusion and new issues they may encounter.
What’s good about the container orchestration field now is that there are automated solutions that can be conveniently put to work. There are Kubernetes troubleshooting platforms designed to address complex K8s errors with all the necessary tools and information developers need.
Solving the Exit Code 1 error can be just a few clicks away. No need to conduct tedious experimentation and use guesswork in the process. The issue can be identified quickly with a timeline for monitoring all changes in apps or the entire cloud infrastructure. These troubleshooting platforms can provide remediation instructions or wizards and allow development teams to troubleshoot errors on their own and avoid the need to escalate the error resolution process.
In Summary
Certainly, the troubleshooting process for Exit Code 1 does represent all the errors that will be encountered in Kubernetes. However, it provides a good glimpse into the complexities of K8s troubleshooting. It shows that there are no compelling reasons to be intimidated by Kubernetes errors or the very idea of using K8s for container orchestration. Troubleshooting can be an easy task for those who patiently find ways to resolve the problem; complicated for those who easily give up and forget all the benefits of Kubernetes after encountering some challenges.
