https://raghavxk8s.com/post/ Recent content in Posts on AI Infra Hugo -- gohugo.io en-us Thu, 23 Mar 2023 23:53:58 +0000 https://raghavxk8s.com/post/onprem-k8s-setup/ Thu, 23 Mar 2023 23:53:58 +0000 https://raghavxk8s.com/post/onprem-k8s-setup/ This doc covers steps to bring up Kubernetes cluster in on premise environment using ansible. Also deploy custom services(own services) Pre-requisites Keep ssh creds(username & ssh_password) for all on premise VMs(master and worker nodes) install ansible (to setup and configure kubernetes) Note: SSH keys provide better security over shh_passwords. Approach (at high level) Create inventory file and add details of master and worker nodes Sample: https://raghavxk8s.com/post/cks/ Wed, 14 Sep 2022 05:02:26 +0000 https://raghavxk8s.com/post/cks/ // TODO: Refer mkDoks SSH security Restrict Kernal modules Open Ports & Listening ports netstat -an | grep -w LISTEN Check ports are used by which services cat /etc/services | grep -w 53 List processes and thier ports netstat -natp netstat -natp | grep "9090" Certificates Check .csr certs information openssl req -text -noout -verify -in CSR.csr SSH adduser username [enter password on the prompt] # Add user to sudo visudo raghav ALL=(ALL:ALL) ALL # Allow passwordless sudo execution raghav ALL=(ALL) NOPASSWD:ALL # Modify user group usermod <user> -G admin # List members of a group groupmems -g <group> -l # SSH config file cat /etc/ssh/sshd_config # Copy public key to remote host ssh-copy-id -i ~/. https://raghavxk8s.com/post/cluster-management/ Sun, 28 Aug 2022 15:29:42 +0000 https://raghavxk8s.com/post/cluster-management/ Upgrading Kubeadm clusters https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/ https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/#call-kubeadm-upgrade-1 Install Network solution https://kubernetes.io/docs/tasks/administer-cluster/network-policy-provider/ Rolling updates of DaemonSets https://kubernetes.io/docs/tasks/manage-daemon/update-daemon-set/ Debug workder nodes Check Kubelet service in worker nodes service kubelet status service kubelet start journalctl -u kubelet Check kubelet service’s certifcates check config file for certs path: /var/lib/kubelet/config.yaml Check kubelet service logs [sudo] journalctl -u kubelet[.service] Note: Any monidifications to kubelet service, pls restart kubelet service kubelet restart https://raghavxk8s.com/post/personal-branding-workshop/ Wed, 11 Aug 2021 12:53:45 +0000 https://raghavxk8s.com/post/personal-branding-workshop/ SWOT Analysis Strengths What are you really good at? learn & adapt quickly Critical thinking Focus on customer use cases task and time management Cross team collaboration Which of the leadership behaviors aligns with your strengths? focus on customer’s use cases task management What skills do other people recognize in you? very sincere & independent Innovative & very focused good thinker & good team player What do you do better than most people you work with? https://raghavxk8s.com/post/personal-branding/ Wed, 11 Aug 2021 06:00:52 +0000 https://raghavxk8s.com/post/personal-branding/ SWOT Analysis Strengths What are you really good at? learn & adapt quickly Critical thinking Focus on customer use cases task and time management Cross team collaboration Which of the leadership behaviors aligns with your strengths? focus on customer’s use cases task management What skills do other people recognize in you? very sincere & independent Innovative & very focused good thinker & good team player What do you do better than most people you work with? https://raghavxk8s.com/post/sample-blog/ Thu, 17 Jun 2021 11:58:41 +0000 https://raghavxk8s.com/post/sample-blog/ In Progress.. asdfas h1 h3 table-data table-data https://raghavxk8s.com/post/go-synchronization/ Tue, 16 Jul 2019 02:24:33 +0000 https://raghavxk8s.com/post/go-synchronization/ *sync.Mutex m := sync.Mutex m.Lock() // for locking m.Unlock() // for unlocking sync.RWMutex m := sync.RWMutex // Read lock & Read unlock. m.RLock() m.RUnlock() // for Write locks & write unlocks m.Lock() m.Unlock() sync.WaitGroup e.g. func main() { var wg sync.WaitGroup wg.Add(1) go func() { fmt.Println("Inside my goroutine") wg.Done() }() wg.Wait() fmt.Println("Finished Execution") } https://raghavxk8s.com/post/python-basics/ Tue, 02 Jul 2019 07:23:07 +0000 https://raghavxk8s.com/post/python-basics/ Open file and Display the whole content f = open("file.txt") print(f.read()) Note: by default the opens in "r"(read) mode; Above code is same as below code f = open("file.txt", "r") print(f.read()) Read first 5 bites of a file f = open("file.txt", "r") print(f.read(5)) Read 10 bites After first 100 bytes f = open("file.txt", "r") print(f.tell()) f.seek(100) print(f.tell()) print(f.read(10)) List all files(recursively) for the directory #!/usr/bin/python import subprocess, os p = subprocess. https://raghavxk8s.com/post/java-collections/ Thu, 20 Jun 2019 19:23:25 +0000 https://raghavxk8s.com/post/java-collections/ Collections Map entry Map<String, String> map = new HashMap<String, String>(); for (Map.Entry<String,String> entry : gfg.entrySet()) System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue()); Loops for(String str : strArray) { System.out.println(str); } Array to list List<Integer> list = Arrays.asList(integerArray) List to Array int[] arr = list.toArray(); Streams Stream<Integer> stream = list.stream(); List<Integer> evenNumbersList = list.stream() .filter(i -> i%2 == 0) .collect(Collectors.toList()); memberNames. https://raghavxk8s.com/post/network-protocals/ Wed, 19 Jun 2019 09:00:58 +0000 https://raghavxk8s.com/post/network-protocals/ Table of Contents TCP UDP TCP (Transmission Control Protocal) * Description : ``` TCP provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network ``` * Its a persistent connection * Three way handshare(at the begining) ``` step1 : Client sends -> I want to talk -> Server step2 : Client recieves <- "Sure. Are you Ready? https://raghavxk8s.com/post/elastic-search-basics/ Mon, 17 Jun 2019 17:15:15 +0000 https://raghavxk8s.com/post/elastic-search-basics/ Elastic Search Concepts Cluster Node Index Type Document Shard Replica Cluster It’s a collection of one or more nodes and holds entire data and provides indexing & search capabilities. Nodes can join a cluster by cluster’s name. Node A node is a single server(part of the cluster) and participates in indexing and search capabilities. Node can be configured to join specific cluster by the cluster name. https://raghavxk8s.com/post/go-types/ Mon, 17 Jun 2019 16:55:16 +0000 https://raghavxk8s.com/post/go-types/ Types Built-in types bool string Numeric: int (either 32 or 64bit) uint (either 32 or 64 bit) uint8, uint16, uint32, uint64 (all Unsigned 8, 16, 32, 64 bit integers respectively) int8, init16, int32 ,int64 (signed integers) float32 float64 Type conversions; T(v) converts value v to T type. a := 10 b := float64(a) var u uint = uint(b) Type Assertion Type assertion takes a value and tries to create another version in the specified explicit type. https://raghavxk8s.com/post/go-functions/ Mon, 17 Jun 2019 16:08:53 +0000 https://raghavxk8s.com/post/go-functions/ function declaration Syntaxt func <nameOfTheFunction>(arg1 typ1, arg2 type2) <returnType> () { ... } e.g. func add(a int, b int) int { return a+b } -- Above function can be written as func add(a, b int) int { } e.g. func location(city string) (state, country string) { ... ... return "BLR", "India" } https://raghavxk8s.com/post/go-variables/ Mon, 17 Jun 2019 14:44:35 +0000 https://raghavxk8s.com/post/go-variables/ Variables declaration in go Declaratoin var ( name string age int city string ) -- var ( name, city string age int ) -- var name string var city string var age int Initialization var ( name string = "Chari" city string = "BLR" mobile int = 12345 ) -- Inferred typing var ( name = "Chari" city = "BLR" mobile = 12345 ) -- var ( name, city, mobile = "Chari", "BLR", 12345 ) Short assignment “:=” (Inside a function only) https://raghavxk8s.com/post/go-format-output/ Mon, 17 Jun 2019 11:30:18 +0000 https://raghavxk8s.com/post/go-format-output/ Printing the verbs General %v the value in a default format when printing structs, the plus flag (%+v) adds field names %#v a Go-syntax representation of the value %T a Go-syntax representation of the type of the value %% a literal percent sign; consumes no value // Examples package main import ( "fmt" ) type rect struct { height float64 width float64 } func main() { r := rect{height : 12, width: 15} fmt. https://raghavxk8s.com/post/go-basics/ Mon, 17 Jun 2019 06:49:18 +0000 https://raghavxk8s.com/post/go-basics/ command line args – main.go package main import ( "os" "fmt" ) func main() { argsWithProgramName := os.Args argsWithoutProgramName := os.Args[1:] fmt.Println(argsWithProg) fmt.Println(argsWithoutProg) } -- OUTPUT -- PS C:\Users\INTEL\Desktop\golang> go run .\main.go "a b c" "sdf" [C:\Users\INTEL\AppData\Local\Temp\go-build928898898\b001\exe\main.exe a b c sdf] [a b c sdf] Reading Files package main import ( "os" "fmt" "bufio" "log" ) func main() { f, err := os.Open("logfile.log") if err != nil { log. https://raghavxk8s.com/post/golang-setup/ Sun, 16 Jun 2019 16:07:54 +0000 https://raghavxk8s.com/post/golang-setup/ Installing Golang on Ubuntu We will be using snappy tool to install go on ubuntu. Ref: snappy Get info for go packages availabe. ``` $ snap info go name: go summary: Go programming language compiler, linker, stdlib publisher: Michael Hudson-Doyle (mwhudson) contact: michael.hudson@ubuntu.com license: unset description: | This snap provides an assembler, compiler, linker, and compiled libraries for the Go programming language. commands: go go.gofmt snap-id: Md1HBASHzP4i0bniScAjXGnOII9cEK6e tracking: stable refresh-date: 2 days ago, at 07:00 IST channels: stable: 1. https://raghavxk8s.com/post/telnet/ Fri, 14 Jun 2019 23:31:18 +0000 https://raghavxk8s.com/post/telnet/ Write content Here https://raghavxk8s.com/post/file-attributes/ Fri, 14 Jun 2019 22:54:41 +0000 https://raghavxk8s.com/post/file-attributes/ Ref: https://serverfault.com/questions/74321/what-happens-to-a-deleted-file-still-subject-to-redirection-on-linux https://linoxide.com/how-tos/howto-show-file-attributes-in-linux/ https://wiki.archlinux.org/index.php/File_permissions_and_attributes https://raghavxk8s.com/post/sed-vs-awk/ Fri, 14 Jun 2019 16:45:35 +0000 https://raghavxk8s.com/post/sed-vs-awk/ sed command Basics -- Replace all 'foo' with 'bar' globally. $ sed -i 's/foo/bar/g' <filename> -- print line from 4 through 15 $ sed -n '4,15p' <file name> -- exclude lines from 10 through 15 $ sed '10,15d' <file-name> -- Display lines from different ranges $ sed -n -e '10,15p'-e '25,35p' <file-name> -- display content of a file after replacing a word $ sed 's/<word>/<new-word>/g' <file-name> -- replacing a word in a file $ sed -i 's/<word>/<new-word>/g' <file-name> -- replace a word and ignore case $ sed -i 's/<word>/<new-word>/gi' <file-name> -- Replace a word or characters in a range $ sed '30,50 s/<word>/<new-word/g' $ sed -i '30,50 s/<word>/<new-word/g' -- swiching multiple matches $ sed -i 's/ \(. https://raghavxk8s.com/post/web-server-vs-app-server/ Fri, 14 Jun 2019 12:04:21 +0000 https://raghavxk8s.com/post/web-server-vs-app-server/ Web Server vs Applicatoin Server Web Server is designed to serve HTTP Content. App Server can also serve HTTP Content but is not limited to just HTTP. It can be provided other protocol support such as RMI/RPC Web Server Servers only web pages. Could be static or Dynamic pages Static Pages HTML CSS JavaScript(Interactively) Dynamic Pages JSP, Servlet (JAVA + HTML + CSS + JavaScript) PHP (PHP + HTML + CSS + JavaScript) ASP. https://raghavxk8s.com/post/bash-shortcuts/ Fri, 14 Jun 2019 09:20:00 +0000 https://raghavxk8s.com/post/bash-shortcuts/ Show and execute most recent command $ echo Hello World! $ !! echo Hello World! Hello World! Execute/View most recent command that starts with given key word $ echo Hello World! $ !echo echo Hello World! Hello World! -- Only view the command(Do not execute) $ !echo:p Option ":p" only prints the command without executing it. Arguments of last command can be referred using ‘!*’ $ echo Hello World! https://raghavxk8s.com/post/sys-admin-cmds-4/ Wed, 12 Jun 2019 17:57:21 +0000 https://raghavxk8s.com/post/sys-admin-cmds-4/ Run levels are Run level 0 is matched by poweroff.target (and runlevel0.target is a symbolic link to poweroff.target). Run level 1 is matched by rescue.target (and runlevel1.target is a symbolic link to rescue.target). Run level 3 is emulated by multi-user.target (and runlevel3.target is a symbolic link to multi-user.target). Run level 5 is emulated by graphical.target (and runlevel5.target is a symbolic link to graphical.target). Run level 6 is emulated by reboot. https://raghavxk8s.com/post/sys-admin-cmds-3/ Wed, 12 Jun 2019 15:53:19 +0000 https://raghavxk8s.com/post/sys-admin-cmds-3/ TODO : extend existing volumes mount $ mount <source> <dest> $ mount /dev/sda2 mountDestDir --- list all mount points $ mount -l --- list all mount points of given type. $ mount -l -t <type> find -- find by name $ find -name <name> -- find not matching name $ find -not -name <name-to-avoid> -- find by type $ find / -type <type> <name> <type> could be one of f = file d = directory l = symbolic link c = character devices b = block devices e. https://raghavxk8s.com/post/iso-model/ Wed, 12 Jun 2019 04:39:33 +0000 https://raghavxk8s.com/post/iso-model/ Layer 7 to Layer 1 All People Seem To Need Data Processing Physical Layer Data Link Lyaer Network Layer Transport Layer Session Presentation Layer Application Layer https://raghavxk8s.com/post/sys-admin-cmds-2/ Wed, 12 Jun 2019 01:22:21 +0000 https://raghavxk8s.com/post/sys-admin-cmds-2/ display inode details for a file $ stat <file> $ stat /etc/passwd --- Output --- File: `/etc/passwd' Size: 2026 Blocks: 8 IO Block: 4096 regular file Device: 811h/2065d Inode: 752010 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2007-08-20 23:19:20.000000000 +0530 Modify: 2007-07-07 00:06:56.000000000 +0530 Change: 2007-07-07 00:06:56.000000000 +0530 Create a user & group --- create a user & group $ sudo useradd -m testuser --- set passwd for the user $ sudo passwd testuser --- create a group sudo groupadd <groupname> $ sudo groupadd testgroup Adding user to a group sudo usermod -a -G <group> <user> $ sudo usermod -a -G testgroup testuser list users for a given group $ grep <username> /etc/group $ grep testuser /etc/group User passwords User encrypted passwords are stored in /etc/shadow. https://raghavxk8s.com/post/terminology/ Tue, 11 Jun 2019 22:28:52 +0000 https://raghavxk8s.com/post/terminology/ * placeholder * abstract it out * Symantics of a command * filesytem is on disk data structure https://raghavxk8s.com/post/to-do/ Tue, 11 Jun 2019 19:14:32 +0000 https://raghavxk8s.com/post/to-do/ java coding, Elastic Search basics, PostgreSQL, Sql coding(basics), nginx setup and configure for two sites on same host https://www.liberiangeek.net/2015/07/how-to-run-multiple-websites-using-nginx-webserver-on-ubuntu-15-04/ sites are usually on location: /var/www/html/example-1.com /var/www/html/example-2.com https://raghavxk8s.com/post/windows-portforward/ Tue, 11 Jun 2019 17:48:16 +0000 https://raghavxk8s.com/post/windows-portforward/ Port forward on Windows 10 > netsh interface portproxy add v4tov4 listenaddress=localhost listenport=8286 connectaddress=192.168.56.101 connectport=8286 List all port forward rules on Windows 10 > netsh interface portproxy show all Delete specific port forward rule > netsh interface portproxy delete v4tov4 listenaddress=localhost listenport=8286 Clear all port forward rules > netsh interface portproxy reset Note: netsh is network shell for windows to configure routings/port forwarding(something like iptables is for linux) https://raghavxk8s.com/post/process/ Tue, 11 Jun 2019 16:51:00 +0000 https://raghavxk8s.com/post/process/ fork vs exec fork creates child process and returns child’s pid child process gets zero as returned value from fork. list by user $ ps -u $USER Ref: https://fedoramagazine.org/inspect-manage-processes-ps/ list processes by group $ ps -G groupname1 groupname2 e.g. $ ps -G root Inverse selection (Using -N option) Select all the process those not started by root(group); $ ps -u root -N Note: htop or top to see how much cpu, ram used for the processes https://raghavxk8s.com/post/tcpdump/ Sun, 19 May 2019 07:53:12 +0000 https://raghavxk8s.com/post/tcpdump/ tcpdump -i any To get the network packets from all network interfaces, run the following command, get packets on localhost with port 8288 tcpdump -i lo0 port 8288 tcpdump -i eth0 get the network packets from a single interface tcpdump -i eth0 -w wirte_file_name write all the captured packets to a file, use the ‘-w’ option, tcpdump -r packets_file read an already created, old tcpdump file. https://raghavxk8s.com/post/sys-admin-cmds-1/ Sun, 19 May 2019 06:34:32 +0000 https://raghavxk8s.com/post/sys-admin-cmds-1/ lscpu list of cpus. lsmem list of memory. lsof (list open files) lsof -i tcp:80 df (disk free space) Display free disk space Filesystem Size Used Avail Use% Mounted on /dev/xvda1 32G 4.7G 26G 16% / tmpfs 1.9G 0 1.9G 0% /dev/shm du (disk space usage) du - estimate file space usage du -sh /var/* id $ id uid=501(operations) gid=100(users) groups=100(users) curl curl -I -s google. https://raghavxk8s.com/post/linux-network-commands-1/ Sat, 18 May 2019 05:30:33 +0000 https://raghavxk8s.com/post/linux-network-commands-1/ Ifconfig Used to configure network interface parameters. Checking ip of the machine. traceroute Print the route packets take to network host. dig(Domain information groper) Dig (domain information groper) query DNS related information like A Record, CNAME, MX Record etc telnet Connects to host on given port using telnet protocal. If connection successful then host is working fine. nslookup It queries internet domain name servers. Options https://raghavxk8s.com/post/vdock-tool/ Thu, 06 Dec 2018 21:19:55 +0000 https://raghavxk8s.com/post/vdock-tool/ Vdock for quickly deploying a site on to Github Go to Vdock Github project https://raghavxk8s.com/post/interview-questions/ Mon, 01 Jan 0001 00:00:00 +0000 https://raghavxk8s.com/post/interview-questions/ https://raghavxk8s.com/post/questions/ Mon, 01 Jan 0001 00:00:00 +0000 https://raghavxk8s.com/post/questions/