My Jenkins server is so slow. Java takes 120% or CPU. How can I give Jenkins more memory access.
Of what steps can I take to improve the load time for Jenkins
If Java memory is causing the problem, then you can add more heap via the -Xmx option, as suggested in Priyam's answer. By default, JVM limits heap to 25% of your available RAM.
More heap has a caveat, though: if you add heap in the range of several GB, then the default JVM garbage collection algorithm will periodically impose stop-the-world breaks in the range of several seconds. You then need to switch to a custom garbage collection algorithm (like, CMS) and then carefully tune its parameters.
If adding more heap does not fix your problem, then you need to dig deeper. There's a plethora of possible root causes for a slow master -- from JVM memory and garbage collection settings to plugin issues, on top of the usual CPU/disk/IO-dimensioning issues.
You can allocate more memory and swap heap sizes using the following commands.
These can be set in the job configuration or Jenkins -> Manage -> Configure
-Xmx512m
-XX:MaxPermSize=128m
Manage Jenkins -> Configure System - > Robot Framework
Deselect checkbox as -> [Display "Robot Results" column in the job list view ]
Please look here for detailed screenshot
Related
I am trying to adjust a build job within jenkins, the problem is, it keeps failing due to lack of memory, I've adjusted java xmx but it did not solve the problem.
Turns out, I have RAM memory limit within the worker, I tried running those commands as part of the build script : "free -m" and "cat /proc/meminfo" and they both confirmed that job is being run with 1GB RAM limit, the server has more but the build isn't using it and it keeps failing due to lack of memory.
Please help me fix this, how can I lift that limit ? thank you
Heap or Permgen?
There are two OutOfMemoryErrors which people usually encounter. The first is related to heap space: java.lang.OutOfMemoryError: Heap space When you see this, you need to increase the maximum heap space. You can do this by adding the following to your JVM arguments -Xmx200m where you replace the number 200 with the new heap size in megabytes.
The second is related to PermGen: java.lang.OutOfMemoryError: PermGen space. When you see this, you need to increase the maximum Permanent Generation space, which is used for things like class files and interned strings. You can do this by adding the following to your JVM arguments -XX:MaxPermSize=128m where you replace the number 128 with the new PermGen size in megabytes.
Also note:
Memory Requirements for the Master
The amount of memory Jenkins needs is largely dependent on many factors, which is why the RAM allotted for it can range from 200 MB for a small installation to 70+ GB for a single and massive Jenkins master. However, you should be able to estimate the RAM required based on your project build needs.
Each build node connection will take 2-3 threads, which equals about 2 MB or more of memory. You will also need to factor in CPU overhead for Jenkins if there are a lot of users who will be accessing the Jenkins user interface.
It is generally a bad practice to allocate executors on a master, as builds can quickly overload a master’s CPU/memory/etc and crash the instance, causing unnecessary downtime. Instead, it is advisable to set up agents that the Jenkins master can delegate jobs to, keeping the bulk of the work off of the master itself.
Finally, there is a monitoring plugin from Jenkins that you can use:
https://wiki.jenkins.io/display/JENKINS/Monitoring
Sources:
https://wiki.jenkins.io/display/JENKINS/Monitoring
https://wiki.jenkins.io/display/JENKINS/Builds+failing+with+OutOfMemoryErrors
https://www.jenkins.io/doc/book/hardware-recommendations/#:~:text=The%20amount%20of%20memory%20Jenkins,single%20and%20massive%20Jenkins%20master.
I've been struggling with a memory consumption issue, my tomcat's mem usage in task manager keeps rising on every request I make to my webapp. I have read that the mem usage in task manager does not necessarily means there is a problem, since it summarizes heap, non-heap and native memory for JVM; however I still am unsure of what exactly is needed to be done in order to decrease the heap memory consumption automatically.
I am using tomcat 7.0.62 and JRE1.8.0_51 with an hibernate3/c3p0 application over a struts2 framework.
In the past few months we have increased functionalities for the application, at first I though it was a memory leak but every time we press the "Perform GC" button in jconsole the heap memory goes down in the graphs, hence the mem usage of the tomcat process stops increasing at the pace it was before.
So far i have set the following properties:
-Dcatalina.home=C:\apache-tomcat-7.0.62
-Dcatalina.base=C:\apache-tomcat-7.0.62
-Djava.endorsed.dirs=C:\apache-tomcat-7.0.62\endorsed
-Djava.io.tmpdir=C:\apache-tomcat-7.0.62\temp
-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
-Djava.util.logging.config.file=C:\apache-tomcat-7.0.62\conf\logging.properties
-Dcom.sun.management.jmxremote.port=6060
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
-XX:+UseParNewGC
-XX:SurvivorRatio=128
-XX:MaxTenuringThreshold=0
-XX:+UseTLAB
-XX:+UseConcMarkSweepGC
-XX:+CMSClassUnloadingEnabled
-XX:+CMSPermGenSweepingEnabled
Is there any configuration parameter missing that you would recommend.
In my tomcat7w console the configuration is as follows:
Thanks in advance.
There are a number of different garbage collectors that can be set when the JVM is started. By default, the gc won't consider running if there is load on the system and still free memory. Use -verbosegc if you want to see how garbage collection is behaving. You can set the maximum heap usage (-Xmx) on startup and gc will kick in more frequently.
I recommend only worrying about it if the server is running other programs and they are being memory starved. The setup you have now is providing the best tomcat performance it can with the resources available.
In Jenkins I have 100 java projects. Each has its own build file.
Every time I want clear the build file and compile all source files again.
Using bulkbuilder plugin I tried compling all the jobs.. Having 100 jobs run parallel.
But performance is very bad. Individually if the job takes 1 min. in the batch it takes 20mins. More the batch size more the time it takes.. I am running this on powerful server so no problem of memory and CPU.
Please Suggest me how to over come this.. what configurations need to be done in jenkins.
I am launching jenkins using war file.
Thanks..
Even though you say you have enough memory and CPU resources, you seem to imply there is some kind of bottleneck when you increase the number of parallel running jobs. I think this is understandable. Even though I am not a java developer, I think most of the java build tools are able to parallelize build internally. I.e. building a single job may well consume more than one CPU core and quite a lot of memory.
Because of this I suggest you need to monitor your build server and experiment with different batch sizes to find an optimal number. You should execute e.g. "vmstat 5" while builds are running and see if you have idle cpu left. Also keep an eye on the disk I/O. If you increase the batch size but disk I/O does not increase, you are consuming all of the I/O capacity and it probably will not help much if you increase the batch size.
When you have found the optimal batch size (i.e. how many executors to configure for the build server), you can maybe tweak other things to make things faster:
Try to spend as little time checking out code as possible. Instead of deleting workspace before build starts, configure the SCM plugin to remove files that are not under version control. If you use git, you can use a local reference repo or do a shallow clone or something like that.
You can also try to speed things up by using SSD disks
You can get more servers, run Jenkins slaves on them and utilize the cpu and I/O capacity of multiple servers instead of only one.
We're running Jenkins server with few slaves that run the builds. Lately there are more and more builds that are running in the same time.
I see the java.exe process on the Jenkins server just increasing , and not decreasing even when the jobs were finnished.
Any idea dwhy oes it happen?
We're running Jenkins ver. 1.501.
Is there a way maybe to make the Jenkins server service ro wait until the last job is finnished, then restart automatically?
I can't seem to find a reference on this (still posting an answer because it's too long for comments ;-) ) but this is what I've observed using the Oracle JVM:
If more memory than currently reserved is needed, the JVM reserves more. So far so good. What it doesn't seem to do is release the memory once it's not needed anymore. You can watch this behaviour by turning on the heap size indicator in Eclipse.
I'd say the same does happen with Jenkins. A running Jenkins with only a few projects already can easily jump the 1 gig mark. If you have a lot of concurrent builds, Jenkins needs a lot of memory at some point. After the builds are done and the heapsize has decreased, the JVM keeps the memory reserved. It is practically "empty" but still claimed by the JVM so it's unavailable for other processes.
Again: It's just an observation. I'd be happy if someone with deeper insight on Java memory management would back this up (or disprove it)
As for a practical solution I'd say you gonna have to live with it to some point. Jenkins IS very hungry for memory. Restarting it solves the problem only temporary. At least it should stop claiming memory at some point because the "empty" reserved memory should be reused. If it's not this really sounds like a memory leak and would be a bug.
Jenkins' [excessive] use of memory without bounds seems to be a common observation. The Jenkins Wiki gives some suggestions for "I'm getting OutOfMemoryErrors".
We have also found that the Monitoring Plugin is useful for keeping an eye on the memory usage and helping us know if we might need to restart Jenkins soon.
Is there a way maybe to make the Jenkins server service ro wait until the last job is finnished, then restart automatically?
Check out the Restart Safely Plugin
in my Grails application using the Spring Security Core plugin for authentication. I am facing a serious problem with that because my application took 21 seconds to lift the Tomcat was carrying 43/2 after installation.
So far so good, but began to occur error 'PermGen Error' memory error Tomcat server. Before it was 64 and Aug is 256 so that the error does not crash my app so often.
I wonder whether you know some plugin configuration in order to reduce the incidence of this error or some method to effect the release of this cache because the number of users is increasing and if you can not solve it unfortunately have to leave the plugin I seems to be an excellent choice for application security.
Someone could tell me if the amount of plugins used in an application interference has this memory?
PermGen is a part of memory to store the static components of your app, mostly classes. Literally it will not be affected by either the amount of users or logs associated with user activities, which consumes heap space instead.
To reduce PermGen storage, you have to check your code, redesign those algorithms which contains unnecessary/redundant objects and operations, and consolidate variables and functions if possible. Generally speaking, simplified code will produce smaller executable files. That's the way you save the PermGen space.
Some versions of Tomcat permgen more than others. There was a minor version in the 6 line that I couldn't every get to reliably stay running. And even with the latest versions you still need to tweak your memory settings. I use the following and it works best for me. I still get them now and again, especially if I'm doing a lot of runtime compiling. In production, it is a non-issue because all the development overhead of grails isn't there.
-XX:MaxPermSize=512m -XX:PermSize=512m -Xms256m -Xmx1024m