This repo is agregated guide for preparation to Devops/SRE engineer interview
Popular Linux Distributions
The most popular linux distrs:
- Ubuntu
- Centos
- Fedora
- Debian
- OpenSuse
- ArchLinux
- Slackware
Comparison: https://www.howtogeek.com/191207/10-of-the-most-popular-linux-distributions-compared/
Linux boot process: from power up to login promt
Explanation:
- BIOS
- MBR
- GRUB
- Kernel
- Init
- Runlevel
Memory types in Linux
Explanation: https://linux-audit.com/understanding-memory-information-on-linux-systems/
What is sticky bit?
Explanation:
What is Virtual memory?
Explanation:
What is zombie process?
Explanation:
File types in Linux
Explanation: https://www.linux.com/tutorials/file-types-linuxunix-explained-detail/
Linux Process Monitor(TOP). Explain all information from top
Explanation:
What is the difference between hardlinks and symlinks?
Explanation:
https://medium.com/@307/hard-links-and-symbolic-links-a-comparison-7f2b56864cdd
What happens if you delete the root user?
Explanation:
- In most cases you will get unbootable system
- https://askubuntu.com/questions/962660/what-happens-if-you-delete-the-root-user
What is a chroot?
Explanation:
https://www.howtogeek.com/441534/how-to-use-the-chroot-command-on-linux/
What is OOM and OOMkiller? How it OOM killer is working
Explanation:
What is kernel panic?
Explanation:
What can you do to restore deleted bash script(script is running but deleted by error)?
Explanation:
See filesystem /proc and find ID proccess in that directory should be script
What happens when a hardlink is removed?
Explanation:
The file will be deleted if you delete only the last hardlink to this file.
Imagine you executed command `chmod -x /bin/chmod`. How to fix this?
Explanation:
Solution1:
cp /bin/cp /tmp/chmod
cp /bin/chmod /tmp/chmod
./tmp/chmod 755 /bin/chmod
Solution2:
perl -e 'chmod(0755, "chmod")`
Solution3:
/lib/ld-linux.so.2 /bin/chmod 755 /bin/chmod
What is Load Average?
Explanation:
http://www.brendangregg.com/blog/2017-08-08/linux-load-averages.html
What are cgroups?
Explanation:
What is NAT?
Explanation:
What is ARP?
Explanation:
Address Resolution Protocol. https://en.wikipedia.org/wiki/Address_Resolution_Protocol
How many layers are there under TCP/IP? Compare OSI and TCP/IP
Explanation:
https://techdifferences.com/difference-between-tcp-ip-and-osi-model.html
EXplain TCP 3-way handshake proccess
Explanation:
Explain DNS records: SOA, PTR, A, MX, and CNAME
Explanation:
How to check route table in Linux?
Explanation:
netstat -rn
route -n
ip route list
Server1 can't reach to Server2. Describe possible reasons
Explanation:
- Application layer: Check if servers are correctly configured and services up and running
- Transport layer: Check ports, check ping from server to server
- Network layer: Check firewall and networking setting. Also check routes, dns and ARP tables.
How to check all of open ports on server?
Explanation:
- nmap - if you need check all ports for remote server
- netstat - for localhost
How to check if the last command was run successfully?
Explanation:
echo $? if returns 0 that last command executed successfully
How would you compare two strings in a bash script?
Explanation: Case1:
#!/bin/bash
VAR1="string1"
VAR2="string333"
if [ "$VAR1" = "$VAR2" ]; then
echo "Strings are equal."
else
echo "Strings are not equal."
fi
Case2:
[[ "string1" == "string2" ]] && echo "Equal" || echo "Not equal"
How to print all array elements and their indexes?
Explanation:
#!/bin/sh
array=("A" "B" "C" "X" )
echo ${array[0]}
How to debug a shell script ?
Explanation:
Option -x
or -nv
Python for sysadmins
Explanation:
SQL vs NoSQL. Explain benefits of both
Explanation:
What are tables and field?
Explanation:
What is GIT?
Explanation:
- https://git-scm.com/book/en/v2/Getting-Started-What-is-Git
- https://git-scm.com/book/en/v2/Getting-Started-What-is-Git
What are the benefits of using GIT?
Explanation:
- Documentation
- Markdown
- Fully Distributed
- Simplicity
- Branching model
- open source
What is the difference between `git pull` and `git fetch` ?
Explanation:
What is the difference between `git reset` and `git revert` ?
Explanation:
What is `git rebase` ?
Explanation:
How to reset last commit?
Explanation:
git reset --hard HEAD~1- not a true way cuz you will lost all changesgit revert <commit-id>- good way
for more https://stackoverflow.com/questions/927358/how-do-i-undo-the-most-recent-local-commits-in-git
Describe a dev/test/production workflow using GIT
Explanation:
- https://medium.com/@patrickporto/4-branching-workflows-for-git-30d0aaee7bf
- https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow
What are the advantages of using Docker container?
Explanation:
Docker RUN vs CMD vs ENTRYPOINT
Explanation:
What is the difference between ADD and COPY in Dockerfile?
Explanation: * https://dev.to/lasatadevi/docker-cmd-vs-entrypoint-34e0
What is docker namespaces?
Explanation:
What is docker multistage build? Create one example
Explanation:
Why we need container orchestration?
Explanation:
What is kubernetes?
Explanation: TODO
What are the features of Kubernetes?
Explanation:
What is kubelet?
Explanation: * Kubelet - agent on a kubernetes cluster’s node that takes care of all activity on that node * https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/
What is CNI?
Explanation:
What is headless service?
Explanation:
What are the units of CPU and memory in POD definition?
Explanation:
- CPU is in milicores and memory in bytes
- https://www.noqcks.io/notes/2018/02/03/understanding-kubernetes-resources/
How to deploy stateful application in Kubernetes?
Explanation:
How to expose Kubernetes service?
Explanation: * https://kubernetes.io/docs/tutorials/kubernetes-basics/expose/expose-intro/
Kubernetes deployments strategies: blue-green, canary, rolling
Explanation: * https://traefik.io/glossary/kubernetes-deployment-strategies-blue-green-canary/
Ansible tutorials
Explanation:
Salt tutorials
Explanation:
What is continuous integration?
Explanation:
What is continuous delivery?
Explanation:
What is continuous deployment?
Explanation:
What are the benefits of CI/CD?
Explanation:
Describe a simple CI/CD Pipeline
Explanation:
https://semaphoreci.com/cicd https://www.redhat.com/en/topics/devops/what-is-ci-cd
Jenkins tutorials
Explanation:
- https://www.udemy.com/share/101WuI/
- https://www.youtube.com/playlist?list=PL9ooVrP1hQOGM6eCsjnfAousUSvpqD8dW&ref=hackr.io
- https://jenkins.io/doc/book/
K8S native CI/CD
Explanation:
- Tekton https://github.com/tektoncd
- ArgoCD https://argoproj.github.io/argo-cd/
- JenkinsX https://jenkins-x.io/
Terraform
Explanation:
http://www.itkitchen.net/k8s-in-gke-with-terraform/ https://www.youtube.com/watch?v=TFLQcgZr0no https://www.udemy.com/share/101ZdI/
What is private cloud?
Explanation:
What is public cloud?
Explanation:
- https://azure.microsoft.com/en-us/overview/what-is-a-public-cloud/
- examples: AWS, GCP, DegitalOcean, Azure
What is cloud service?
Explanation:
AWS tutorials
Explanation:
Google Cloud tutorials
Explanation:
Openstack tutorials
Explanation:
The best resource with Openstack cources is LinuxAcademy https://linuxacademy.com/library/search/openstack/
- Brendan Gregg http://www.brendangregg.com/blog/index.html
- Systems Performance http://www.brendangregg.com/sysperfbook.html
- The Phoenix project https://www.amazon.com/Phoenix-Project-DevOps-Helping-Business/dp/1942788290/
- SRE https://landing.google.com/sre/books/
- Linux System Administration Handbook 5th by Evi Nemeth
- The DevOps Handbook: How to Create World-Class Agility, Reliability, and Security in Technology Organizations
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent