Site Reliability Engineer (SRE) is a role within an organization that is responsible for ensuring the reliability, performance, and uptime of the company’s systems and applications. SREs work closely with development teams to design, build, and maintain scalable and reliable systems, and use a combination of software engineering and operations skills to improve the reliability and performance of the company’s systems.

Here are some tips for debugging as an SRE

1. Gather as much information as possible : Before starting to debug, try to gather as much information as possible about the problem. This might include logs, error messages, system metrics, and any relevant configuration files.

2. Break down the problem : Identify the specific component or subsystem that is causing the problem and focus on that. This will help you narrow down the scope of the problem and make it easier to troubleshoot.

3. Use tools and resources : There are many tools and resources available to help with debugging, such as log analysis tools, monitoring systems, and system profiling tools. Make use of these to help identify the cause of the problem.

4. Create test cases : Create test cases to help you isolate the problem and verify that it has been fixed. This will help you confirm that the problem has been resolved and ensure that it does not reoccur in the future.

5. Collaborate with others : Don’t be afraid to ask for help or collaborate with others. Often, other people can bring fresh perspectives and ideas to the problem, which can help you find a solution more quickly.

6. Document your work : Document the steps you took to debug the problem and the solution you implemented. This will help you understand the problem better and make it easier to troubleshoot similar issues in the future.

Best Practices for SRE

1. Monitor and alert on key performance indicators (KPIs) : Monitor key performance indicators (KPIs) for your systems and applications, and set up alerts to notify you when something goes wrong. This will help you quickly identify and resolve problems before they become critical.

2. Automate repeatable tasks : Automate as many repeatable tasks as possible to reduce the risk of human error and improve efficiency. This might include tasks such as provisioning new servers, deploying code updates, or creating backups.

3. Use version control : Use version control to manage and track changes to your systems and applications. This will help you easily roll back changes if something goes wrong, and make it easier to collaborate with other team members.

4. Implement a change management process : Implement a change management process to ensure that all changes to your systems and applications are properly documented, tested, and reviewed before being deployed. This will help you minimize the risk of errors and downtime.

5. Use testing and staging environments : Use testing and staging environments to validate changes before deploying them to production. This will help you identify and fix problems before they impact your users.

6. Practice disaster recovery : Regularly practice disaster recovery scenarios to ensure that you are prepared to handle unexpected events. This might include backing up data, testing failover processes, and simulating outages.

7. Document processes and procedures : Document processes and procedures for common tasks, such as troubleshooting, deployment, and maintenance. This will help you and other team members understand how your systems work and how to fix problems when they arise.

Here is a list of 100 Linux commands that a SRE (Site Reliability Engineer) might find useful, along with brief descriptions and code examples for each:

1. ls - List directory contents

    ls

2. cd - Change directory

    cd /path/to/directory

3. pwd - Print working directory

    pwd

4. mkdir - Create a new directory

    mkdir new_directory

5. rmdir - Remove a directory

    rmdir directory_to_remove

6. cp - Copy files and directories

    cp file1 file2
    cp -r directory1 directory2

7. mv - Move or rename files and directories

    mv file1 file2
    mv directory1 directory2

8. rm - Remove files and directories

    rm file1 file2
    rm -r directory1 directory2

9. touch - Create a new file or update the timestamp of an existing file

    touch new_file

10. echo - Print a message or the value of a variable to the terminal

    echo "Hello, world!"

11. cat - Display the contents of a file

    cat file1 file2

12. less - View the contents of a file one page at a time

    less file

13. head - Display the first few lines of a file

    head file

14. tail - Display the last few lines of a file

    tail file

15. grep - Search for a pattern in a file or stream

    grep "pattern" file

16. find - Search for files and directories

    find /path/to/search -name "pattern"

17. sort - Sort the lines of a file or stream

    sort file

18. uniq - Remove duplicate lines from a file or stream

    sort file | uniq

19. wc - Count the number of lines, words, and bytes in a file or stream

    wc file

20. chmod - Change the permissions of a file or directory

    chmod u+x file

21. chown - Change the owner of a file or directory

    chown owner:group file

22. diff - Compare the contents of two files

    diff file1 file2

23. patch - Apply a patch file to modify the contents of a file

    patch file < patch_file

24. tar - Create or extract a tar archive

    tar -cvf archive.tar file1 file2
    tar -xvf archive.tar

25. gzip - Compress or decompress a file using gzip

    gzip file
    gunzip file.gz

26. diff - Compare the contents of two files

    diff file1 file2

27. curl - Transfer data using various network protocols

    curl https://www.example.com

28. wget - Download a file from the web

    wget https://www.example.com/file.txt

29. scp - Securely copy files between hosts

    scp file user@remote:/path/to/destination

30. rsync - Synchronize files and directories between hosts

    rsync -avz source/ user@remote:/path/to/destination/

31. ssh - Connect to a remote host using a secure shell

    ssh user@remote

32. ping - Test the reachability of a host

    ping www.example.com

32. traceroute - Trace the route packets take to a destination host

    traceroute www.example.com

33. nslookup - Query DNS to obtain information about a host

    nslookup www.example.com

34. dig - Query DNS to obtain detailed information about a host

    dig www.example.com

35. host - Query DNS to obtain information about a host

    host www.example.com

36. whois - Look up information about a domain name or IP address

    whois www.example.com

37. nmap - Scan networks for hosts and services

    nmap -sS 192.168.0.0/24

38. tcpdump - Capture and analyze network traffic

    tcpdump -i eth0

39. nc - Connect to or listen for network connections

    nc -l 1234
    nc www.example.com 80

40. telnet - Connect to a remote host using the telnet protocol

    telnet www.example.com 80

41. ftp - Transfer files using the FTP protocol

    ftp ftp.example.com

42. sftp - Transfer files securely using the SFTP protocol

    sftp user@remote

43. rlogin - Connect to a remote host using the rlogin protocol

    rlogin user@remote

44. rsh - Connect to a remote host using the rsh protocol

    rsh user@remote

45. top - Display real-time information about running processes

    top

46. ps - Display information about running processes

    ps aux

47. kill - Send a signal to a process to terminate it

    kill -9 12345

48. killall - Terminate all processes with a specific name

    killall process_name

50. nice - Run a program with a modified scheduling priority

    nice -n 19 command

51. cron - Schedule tasks to be run automatically

    crontab -e

52. at - Schedule a command to be run at a specific time

    at now +1 hour

53. screen - Create and manage multiple terminal sessions

    screen -S session_name

54. tmux - Create and manage multiple terminal sessions

    tmux new -s session_name

55. htop - Display real-time information about running processes with a interactive interface

    htop

56. iotop - Display real-time information about I/O usage by processes

    iotop

57. lsof - List open files and the processes that have them open

    lsof

58. df - Display information about available disk space

    df -h

59. du - Estimate the space used by a file or directory

    du -sh /path/to/directory

60. fuser - Identify processes using a specific file or filesystem

    fuser /path/to/file

61. chroot - Change the root filesystem for a command or shell

    chroot /new/root command

62. chkconfig - Manage system service startup links

    chkconfig --list
    chkconfig service_name on

63. systemctl - Manage system services and daemons

    systemctl list-units
    systemctl start service_name

64. service - Manage system services

    service --status-all
    service service_name start

65. init - Manage system initialization and runlevel changes

    init 3

66. reboot - Reboot the system

    reboot

67. shutdown - Shut down the system

    shutdown -h now

68. date - Display or set the system date and time

    date
    date -s "2 OCT 2006 18:00:00"

69. timedatectl - Manage the system time and timezones

    timedatectl
    timedatectl set-timezone America/New_York

70. hwclock - Manage the system hardware clock

    hwclock
    hwclock --systohc

71. ntpdate - Set the system clock using NTP

    ntpdate pool.ntp.org

72. ntpq - Query NTP servers

ntpq -p

73. ntpd - Synchronize the system clock using NTP

    ntpd -q

74. syslogd - System logging daemon

    syslogd -f /etc/syslog.conf

75. rsyslogd - Enhanced system logging daemon

    rsyslogd -f /etc/rsyslog.conf

76. journalctl - Query and display the system journal

    journalctl
    journalctl -u service_name

77. dmesg - Display kernel ring buffer messages

    dmesg

78. ulimit - Control process resource limits

    ulimit -n 1024

79. free - Display information about memory usage

    free -m

80. vmstat - Display information about virtual memory usage

    vmstat

81. iostat - Display information about I/O usage

    iostat

82. mpstat - Display information about CPU usage

    mpstat

83. sar - Collect and report system performance statistics

    sar

84. uptime - Display system uptime and load average

    uptime

85. last - Display information about previous logins

    last

86. w - Display information about logged in users

    w

87. who - Display information about logged in users

    who

88. finger - Display information about users

    finger user

89. id - Display information about a user

    id user

90. groups - Display the groups a user is a member of

    groups user

91. passwd - Modify a user’s password

    passwd

92. adduser - Add a new user to the system

    adduser new_user

93. useradd - Add a new user to the system

    useradd new_user

94. deluser - Remove a user from the system

    deluser user

95. userdel - Remove a user from the system

    userdel user

96. groupadd - Add a new group to the system

    groupadd new_group

97. groupdel - Remove a group from the system

    groupdel group

98. visudo - Edit the sudoers file

    visudo

99. sudo - Execute a command with root privileges

    sudo command

100. renice - Modify the scheduling priority of a running process

    renice -n 19 -p 12345