Linux & App Servers Monitoring Tricks

LINUX & APPLICATION SERVERS MONITORING TRICKS


Objective:

  • Prevent server from going down,
  • detect what caused the server to go down,
  • get servers back after failure.
  • Explain what caused the server to fail

I – Regularly watch your monitoring  tool(s) (Nagios, Wily,top, …..)

On some of those tools,  you can see a graph of the apps CPU Load Average, CPU Used Percentage, Disk Usage percentage, memory used percentage, Network Bandwidth, Swap Used percentage.

II – Check ulimit count (Number of files opened by applications like tomcat, oracle,…)

[Server]# ulimit -n
1024
If the number of files opened is getting closer to ulimit count (1024), increase the ulimit and talk to dev to identify and fix the process that is causing that.
To increase ulimit count for a specific application account, run the command  ulimit –n [value]
Ulimit can be set to whatever you want. Its one of those things that’s put in place as a throttle to keep things from going too nuts. Some systems will actually just set it to unlimited.

III- Port Monitoring 
Check number of connections to ports used by your apps

IV- Thread dump (stack trace of all threads ) If you have a high cpu percentage

[Server]# kill -3 (The output is printed in catalina.out) to see what is causing this and send it to developers.

V- Disk space /[drive_name] filling up quickly
Identify the file(s) that are filling up the disks. Most of the time ,it will be logs files.
[Server]# du -ks /[drive_name]/* | sort -nr | head
5719076 /[drive_name]/catalina
3675672 /[drive_name]/data
3287436 /[drive_name]/source
2044316 /[drive_name]/servers
319404 /[drive_name]/images
16 /[drive_name]/lost+found
By running this command on the larger folder, that will lead you to the files that eat the disk space.
Back up, remove or empty the file in question given that it won’t break the system.
If the log files are responsible for the disk filling up, let the developer know about it so that they can solve it. In the meantime, empty the log file with the command:

[Log_File_Location]# echo -n > Large_Log_File_Name.log

VI- Watch catalina.out and log4j.out after staging and live deploy, especially when you are restarting the servers.

 

[Server]# tail -f log4j.log
VII- Start app servers properly
Before restarting app servers, make sure there is no app pid running for that specific server.

[Server_Name]$ ps -ef | grep oracle
Kill the pid for that server.

IX – Cpu Load level

I would say that if we peak under 70% CPU during high traffic, we are doing well and have room. A good level to be ticking over at would be 30% used.
[Server]# top
top – 12:37:29 up 47 days, 23:09, 4 users, load average: 0.20, 0.20, 0.22
Tasks: 189 total, 1 running, 178 sleeping, 10 stopped, 0 zombie
Cpu(s): 1.2%us, 0.1%sy, 0.0%ni, 97.5%id, 1.0%wa, 0.0%hi, 0.1%si, 0.0%st

X- Server specific status pings (To assure the server are up and serving contents)
Write scripts for this

XI- Garbage collection stats

If you are interested in any garbage collection stats there’s the gc.log files on each of the appservers (bad thing about it is it doesn’t do any date stamping so you can see how memory fluctuates but its a difficult to create a chart over time). In the past I’ve thought it might be good idea to write a cron that archived it daily so that you could at least break things down day by day.

XII- DB Connection

XIII- Load Average Monitoring script
Set up a  cron that just email sysadmin when the load average is above 3.

XIV – Find out who is monopolizing or eating the CPUs
[Server]# ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10


AI Unraveled: Demystifying Frequently Asked Questions on Artificial Intelligence (OpenAI, ChatGPT, Google Gemini, Generative AI, Discriminative AI, xAI, LLMs, GPUs, Machine Learning, NLP, Promp Engineering)
Ace the 2023 AWS Solutions Architect Associate SAA-C03 Exam with Confidence Pass the 2023 AWS Certified Machine Learning Specialty MLS-C01 Exam with Flying Colors

List of Freely available programming books - What is the single most influential book every Programmers should read



#BlackOwned #BlackEntrepreneurs #BlackBuniness #AWSCertified #AWSCloudPractitioner #AWSCertification #AWSCLFC02 #CloudComputing #AWSStudyGuide #AWSTraining #AWSCareer #AWSExamPrep #AWSCommunity #AWSEducation #AWSBasics #AWSCertified #AWSMachineLearning #AWSCertification #AWSSpecialty #MachineLearning #AWSStudyGuide #CloudComputing #DataScience #AWSCertified #AWSSolutionsArchitect #AWSArchitectAssociate #AWSCertification #AWSStudyGuide #CloudComputing #AWSArchitecture #AWSTraining #AWSCareer #AWSExamPrep #AWSCommunity #AWSEducation #AzureFundamentals #AZ900 #MicrosoftAzure #ITCertification #CertificationPrep #StudyMaterials #TechLearning #MicrosoftCertified #AzureCertification #TechBooks

Top 1000 Canada Quiz and trivia: CANADA CITIZENSHIP TEST- HISTORY - GEOGRAPHY - GOVERNMENT- CULTURE - PEOPLE - LANGUAGES - TRAVEL - WILDLIFE - HOCKEY - TOURISM - SCENERIES - ARTS - DATA VISUALIZATION
zCanadian Quiz and Trivia, Canadian History, Citizenship Test, Geography, Wildlife, Secenries, Banff, Tourism

Top 1000 Africa Quiz and trivia: HISTORY - GEOGRAPHY - WILDLIFE - CULTURE - PEOPLE - LANGUAGES - TRAVEL - TOURISM - SCENERIES - ARTS - DATA VISUALIZATION
Africa Quiz, Africa Trivia, Quiz, African History, Geography, Wildlife, Culture

Exploring the Pros and Cons of Visiting All Provinces and Territories in Canada.
Exploring the Pros and Cons of Visiting All Provinces and Territories in Canada

Exploring the Advantages and Disadvantages of Visiting All 50 States in the USA
Exploring the Advantages and Disadvantages of Visiting All 50 States in the USA


Today I Learned (TIL) You learn something new every day; what did you learn today? Submit interesting and specific facts about something that you just found out here.

Reddit Science This community is a place to share and discuss new scientific research. Read about the latest advances in astronomy, biology, medicine, physics, social science, and more. Find and submit new publications and popular science coverage of current research.

Reddit Sports Sports News and Highlights from the NFL, NBA, NHL, MLB, MLS, and leagues around the world.

Turn your dream into reality with Google Workspace: It’s free for the first 14 days.
Get 20% off Google Google Workspace (Google Meet) Standard Plan with  the following codes:
Get 20% off Google Google Workspace (Google Meet) Standard Plan with  the following codes: 96DRHDRA9J7GTN6 96DRHDRA9J7GTN6
63F733CLLY7R7MM
63F7D7CPD9XXUVT
63FLKQHWV3AEEE6
63JGLWWK36CP7WM
63KKR9EULQRR7VE
63KNY4N7VHCUA9R
63LDXXFYU6VXDG9
63MGNRCKXURAYWC
63NGNDVVXJP4N99
63P4G3ELRPADKQU
With Google Workspace, Get custom email @yourcompany, Work from anywhere; Easily scale up or down
Google gives you the tools you need to run your business like a pro. Set up custom email, share files securely online, video chat from any device, and more.
Google Workspace provides a platform, a common ground, for all our internal teams and operations to collaboratively support our primary business goal, which is to deliver quality information to our readers quickly.
Get 20% off Google Workspace (Google Meet) Business Plan (AMERICAS): M9HNXHX3WC9H7YE
C37HCAQRVR7JTFK
C3AE76E7WATCTL9
C3C3RGUF9VW6LXE
C3D9LD4L736CALC
C3EQXV674DQ6PXP
C3G9M3JEHXM3XC7
C3GGR3H4TRHUD7L
C3LVUVC3LHKUEQK
C3PVGM4CHHPMWLE
C3QHQ763LWGTW4C
Even if you’re small, you want people to see you as a professional business. If you’re still growing, you need the building blocks to get you where you want to be. I’ve learned so much about business through Google Workspace—I can’t imagine working without it.
(Email us for more codes)