Troubleshooting Some Common Issues While Implementing/Running Docker – 2023
Has Docker been put into use in production yet? Here are a few crude fixes for issues that frequently arise during development.
Docker is an excellent tool. However, Docker containers are not a solution. You must comprehend Docker's constraints to fully comprehend how it affects the channel.
Docker containers have exploded in popularity over the past few years due to their advantages over virtual machines, including their ability to expand more simply and start up more quickly.
Introduction
Docker makes it simple to package your services and apps in containers so you can execute them wherever you are. However, if you're unfamiliar with Docker images and containers, issues may occur while creating your picture and merging all of the components that your program needs.
Typographical errors, problems with runtime packages and extensions, naming conflicts, and communication problems with other containers are all possible.
This troubleshooting tutorial for Docker beginners explains how to repair difficulties with creating Docker images, dealing with name conflicts while hosting containers, and debugging communication issues between containers.
Shortcomings of using Docker
Examples of what Docker can't or can't accomplish well are as follows:
Lack of cross-platform interoperability
Linux cannot run an application created for Windows to operate in a Docker container, and vice versa. This restriction does not apply to virtual computers. This makes Docker less desirable in setups that are very diverse and comprise both Windows and Linux systems.
You are required to run graphical user interface-based programs.
Docker was created as a tool for hosting command-line-based programs. It is feasible to run a graphical interface within a Docker container using various methods (like X11 forwarding), but this is cumbersome. In actuality, Docker is a poor choice for apps that demand elaborate interfaces.
Run programs as quickly as a server made of bare metal.
Virtual machines have more overhead than Docker containers. However, Docker has some overhead. Running an application directly on a bare-metal server, without utilizing containers or virtual machines, is the only method to achieve genuine bare-metal speed from it.
Security challenges
Through the isolation of apps from the target host and one another, Docker can enhance security in several ways. Containers also make it simple to divide your application into smaller pieces so that the remainder is not necessarily impacted if one is broken. Docker also introduces other security difficulties, such as the issue of keeping track of so many working parts in a continuous, massive Docker architecture. You must assess the security risks unique to Docker and ensure you can manage them before migrating operations to it.
However, Docker can't meet all of your demands, just as the cloud is not appropriate in every circumstance. Containers provide several advantages over more traditional application deployment technologies.
Best Practices to Avoid Common Issues While Implementing/Running Docker
Reboot
To stop and remove any leftover instances of the daemon from the fully installed version, reboot your computer.
Verify Docker is operating before using the webserver examples.
To access the web server at http://localhost/ for the hello-world-nginx example and other ones, Docker Desktop has to be running. As well as running the Docker operations in a terminal that is linked to the Docker Desktop Engine, ensure the Docker whale is visible in the menu bar. If not, you could run the webserver container, visit docker, and get a "web page not available" message.
Removing DOCKER HOST
There is no requirement to specify the local variable DOCKER HOST. Use the instruction unset ${!DOCKER_*} to autodetect it if you're using bash. Read the instructions for the shell to learn about different shells.
Fixing issues related to port allocation
If you have issues such as Bind for 0.0.0.0:8080 failed: is already in use or waiting on port 0.0.0.0:8080: Location already in use by bind
Other Windows program accessing those ports frequently results in the same issues. Use the resmon.exe GUI's "Network" and "Listening Ports" buttons to identify this program, or use the Powershell command netstat -on | find /i "listening" to identify the PID of the process that is presently utilizing the channel. Choose whether to terminate the other operation or change your Docker app's port.
When Docker Desktop doesn't launch after installing antivirus software
Certain antivirus programs might not work with Hyper-V and some versions of Windows 10. The problem often shows as an error message from the Docker daemon and an inability to start Docker Desktop following a Windows upgrade.
Uninstall the antivirus program or look at other alternatives that have been recommended in Docker Desktop forums as a temporary fix.
Important steps involved in troubleshooting issues
The critical steps for debugging Docker Desktop for Windows and Docker-based development are shown below.
Check the records
Check the container records or the engine records, based on the problem. See the Sitecore Docker cheat page for information on viewing container logs. Additionally, you may see logs using the various tools mentioned above as well as the Docker Desktop (Dashboard).
Not all built-in Sitecore database systems stream by default for Cfor CM and CD images by default become excessive if you add them to the LogMonitor configuration (c:LogMonitorLogMonitorConfig.json). Bind mounting the Sitecore log folder is useful, as seen in the Docker Examples archive:
The logs for the Docker engine (daemon) may be found in C: Users%USERNAME%AppDataLocal%Docker.
Reload Docker Desktop
Frequently, problems may be solved by resetting Docker Desktop. With the whale symbol on the Windows system panel, you may restart Docker.
If your applications use plotted volumes for data replication, make sure that the data in those folders is clean. This can solve your problem. For the MySQL and solr functions, this is enabled by default in settings. Ensure your server is down (using docker-compose down), then manually or using a clean script remove any files from the mounted directories.
Clean up unneeded Docker resources if you haven't already. Prune Docker resources. At the very least, adopting this daily routine will help you clear up disc space:
Restart your computer
In certain cases, a system reload can help.
Upgrade to the most recent version of Docker Desktop for Windows
Docker consistently releases updates to Docker Desktop for Windows that include bug fixes and enhancements. The Docker item (whale logo) in the Windows system prompt may be used to check for updates.
Restore Docker Desktop to its default settings
By doing this, Docker Desktop's settings are restored to their original, pre-installation condition. From the Troubleshoot menu of the Docker item (whale logo) on the Windows system tray, you may perform this action.
Memory use in the container environment
When using Sitecore Containers, Sitecore recommends 32GB of RAM for development workstations, with 16GB being the minimum. Try lowering your environment's memory use if you are experiencing errors or performance issues as a result of inadequate system memory.
Replace the XP1 topology with an XM1 or XP0 one.
Run a customized XM1 topology for XM0. You accomplish this by using the Sitecore AppSettings role: define default values to set the Redis and cd servers to measure: 0 and the cm utility to autonomous mode.
Change to the 1909-based Core modules and program separation using the SITECORE VERSION and ISOLATION variables if your version of Windows 10 supports doing so:
Configure memory restrictions for each container. Although Docker consumes 1GB by default, you may lower that for some services. Don't do that for the MSSQL or Solr services, though.
For containers that you do not require, deactivate functions. If you don't utilize the Online Marketing System, for instance, deactivate the xdbautomationworker, xdbautomation, and xdbautomationrpt in an XP1 topology. Similarly, deactivate the cortexprocessingworker, cortexprocessing, and cortexreporting.
When Internet connectivity is not possible for Windows containers
This could appear as a connection error during a NuGet reset procedure, among other things.
Citing problem response 430889666 from https://github.com/docker/for-win/issues/2760.
When the host has several connectivity interfaces (such as Ethernet and Wi-Fi), this frequently occurs. For the Windows protocol stacks to pick port pathways appropriately, you must properly specify the importance of these interfaces. This may be resolved by lowering the InterfaceMetric value on your main networking adapter that connects to the internet:
To alter, enter the following command (this sample assumes that the main adapter's InterfaceAlias is "Wi-Fi"):
If you have an extra switch configured in Hyper-V and the main networking interface on your host is spanned, configure the external network interface to have the minimum InterfaceMetric number.
If Containers remain in their Created state.
This problem commonly appears after using a virtual machine. When you verify with docker ps -a, some services could fail to start but instead return a Created level.
Increase the RAM limit for troublesome processes in your Docker Compose document to see if it helps. The 1GB baseline for Docker may not be enough for some services. For instance, the MySQL and solr service containers could need 2GB:
If Admin login is not allowed
This can happen when the Sitecore admin password (SITECORE ADMIN PASSWORD variable) has been updated and durable SQL storage arrays are enabled (through a mounted disc in your Docker Compose setup). The password is established when the MySQL entries are first generated, thus if your version was started (i.e., with Kubernetes up) before the credential update, it is no longer valid.
This is allowed in the default Sitecore setup, and the drive is connected to the MySQL data inbox:
To fix this, make sure your version is down (Kubernetes down) and remove the connected folder's files. These may be removed by hand or with a clean script.
Conclusion
From creating images to installing a network of containers, we just went over the most frequent problems you could run across while dealing with Docker containers.
Although software containers have been around for a while, Docker has only been around for three years and may be rather complicated. You'll discover how certain ideas that once seemed a little strange will quickly make a lot of sense if you take your time to become comfortable with the vocabulary and the ecosystem.
Frequently Asked Questions (FAQs)
What is Docker?
To guarantee that your application functions without a hitch in any context, whether it is development, trial, or release, Docker is a containerization platform that puts your application and all of its components together in the form of containers.
How does containerization work?
Let me provide an example to illustrate this. Code created on one system may not always function flawlessly on any other machine during the software development process due to dependencies.
What is Docker Swarm?
A native microservices tool called Docker Swarm is produced by Docker Inc. It enables us to coordinate the operation of our containers, much like Docker Compose but for production use.
What Are the Best Practices for Containers?
The following are some essential reminders:
Containers should always log to STDOUT; this standardizes logging and makes it simple to use monitoring tools to keep track of activity.
Permanent data shouldn't be stored in containers.
Data should be kept outside the container.
Comments
Post a Comment