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Kubernetes Without kube-proxy

Kubernetes Without kube-proxy Quick-Start kubeadm init --skip-phases=addon/kube-proxy # Setup Helm repository helm repo add cilium https://helm.cilium.io/ helm install cilium cilium/cilium --version 1.9.18 \ --namespace kube-system \ --set kubeProxyReplacement=strict \ --set k8sServiceHost=REPLACE_WITH_API_SERVER_IP \ --set k8sServicePort=REPLACE_WITH_API_SERVER_PORT

Monday, December 20, 2021 Read

Zsh tab-completion not working

Zsh tab-completion not working Question Although I’ve used Oh-My-Zsh in the past, I decided this time around (i.e. setting up a new computer) I’d try to avoid installing it to keep things a bit leaner. Right now I’m trying to cherry-pick Oh-My-Zsh’s insensitive tab-completion feature. Digging around its source repo, I found the following line: zstyle ':completion:*' matcher-list 'm:{a-zA-Z}={A-Za-z}' 'r:|=*' 'l:|=* r:|=*' I’m fairly confident this is the line Oh-My-Zsh executes to do what I want, so I tried adding it to my .zshrc. Restarted my terminal. Typed cd desk, then hit [tab]. No dice – I didn’t get cd Desktop/.

Friday, December 10, 2021 Read

Linkerd 2.8 - Build a Simple and Secure Multi-Cluster Kubernetes Architecture

Thursday, December 9, 2021 Read

Best Practices for Writing Bash Scripts

Best Practices for Writing Bash Scripts Shell Scripting - Best Practices #!/usr/bin/env bash # Bash3 Boilerplate. Copyright (c) 2014, kvz.io set -o errexit set -o pipefail set -o nounset # set -o xtrace # Set magic variables for current file & dir __dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)" __file="${__dir}/$(basename "${BASH_SOURCE[0]}")" __base="$(basename ${__file} .sh)" __root="$(cd "$(dirname "${__dir}")" && pwd)" # <-- change this as it depends on your app arg1="${1:-}" Use shift to read function arguments This makes it easier to reorder arguments, if you change your mind later.

Monday, December 6, 2021 Read

Day 28 - Introduction to Useful Third-Party Kubernetes Tools

Day 28 - Introduction to Useful Third-Party Kubernetes Tools $ kubectl get pods NAME READY STATUS RESTARTS AGE ithome-6564f65698-947rv 1/1 Running 0 84s ithome-6564f65698-fglr9 1/1 Running 0 84s ithome-6564f65698-k5wtg 1/1 Running 0 84s ithome-6564f65698-rrvk4 1/1 Running 0 84s ithome-6564f65698-zhwlj 1/1 Running 0 84s Stern/Kail The names of created pods often contain some unreadable random strings. If you use kubectl to observe logs for individual pods, you need to switch between different pods. There are many tools for this, such as Stern, Kube-tail, and Kail.

Thursday, December 2, 2021 Read

5 DevSecOps open source projects to know

5 DevSecOps open source projects to know Clair Sigstore KubeLinter Open Policy Agent and Gatekeeper Falco

Tuesday, November 30, 2021 Read

[Kubernetes] Service Overview

[Kubernetes] Service Overview Define Service With selector Since you need Pods before you define a Service, assume there are Pods in the cluster (exposing TCP port 9376) with the label app=MyApp. You can define a Service as an abstraction layer in front of those pods and provide the service through a domain name. kind: Service apiVersion: v1 metadata: name: my-service spec: # type has four options (ClusterIP, NodePort, LoadBalancer, ExternalName) # default is ClusterIP type: ClusterIP # select pods with "app=MyApp" selector: app: MyApp # Service port configuration ports: - protocol: TCP port: 80 # This is the port number exposed by the Pod targetPort: 9376 Pod <---> Endpoint(tcp:9376) <---> Service(tcp:80, with VIP)

Wednesday, November 24, 2021 Read

How Go Reads a 16GB File in 25 Seconds

How Go Reads a 16GB File in 25 Seconds Reading 16GB File in Seconds, Golang After opening the file, we have two options: Read the file line by line, which reduces memory pressure but takes more time. Read the entire file into memory and process it, which uses more memory but significantly reduces time. Because the file is too large (16 GB), we cannot load the entire file into memory. But the first option is also not feasible for us because we want to process the file within seconds.

Monday, November 22, 2021 Read

Bind JSON with jsoniter in Gin

Bind JSON with jsoniter in Gin simple go build -tags=jsoniter ./... custom implement BindingBody interface // github.com/gin-gonic/gin@v1.6.3/binding/binding.go:36 // Binding describes the interface which needs to be implemented for binding the // data present in the request such as JSON request body, query parameters or // the form POST. type Binding interface { Name() string Bind(*http.Request, interface{}) error } // BindingBody adds BindBody method to Binding. BindBody is similar with Bind, // but it reads the body from supplied bytes instead of req.Body. type BindingBody interface { Binding BindBody([]byte, interface{}) error } package custom import ( "bytes" "fmt" "io" "net/http" jsoniter "github.com/json-iterator/go" "github.com/gin-gonic/gin/binding" ) // BindingJSON replaces Gin's default binding and supports richer JSON features var BindingJSON = jsonBinding{} // You can customize jsoniter config or add plugins var json = jsoniter.ConfigCompatibleWithStandardLibrary type jsonBinding struct{} func (jsonBinding) Name() string { return "json" } func (jsonBinding) Bind(req *http.Request, obj interface{}) error { if req == nil || req.Body == nil { return fmt.Errorf("invalid request") } return decodeJSON(req.Body, obj) } func (jsonBinding) BindBody(body []byte, obj interface{}) error { return decodeJSON(bytes.NewReader(body), obj) } func decodeJSON(r io.Reader, obj interface{}) error { decoder := json.NewDecoder(r) if binding.EnableDecoderUseNumber { decoder.UseNumber() } if binding.EnableDecoderDisallowUnknownFields { decoder.DisallowUnknownFields() } if err := decoder.Decode(obj); err != nil { return err } return validate(obj) } func validate(obj interface{}) error { if binding.Validator == nil { return nil } return binding.Validator.ValidateStruct(obj) } // Replace binding.JSON with the custom one ctx.ShouldBindWith(ms, binding.JSON) ctx.ShouldBindBodyWith(ms, binding.JSON)

Monday, November 22, 2021 Read

Golang os/exec usage (notes)

Golang os/exec usage (notes) Add extra environment variables before running a command cmd := exec.Command("programToExecute") additionalEnv := "FOO=bar" newEnv := append(os.Environ(), additionalEnv) cmd.Env = newEnv out, err := cmd.CombinedOutput() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) } fmt.Printf("%s", out) Use os/exec with pipes or bash expressions on Linux rcmd := `iw dev | awk '$1=="Interface"{print $2}'` cmd := exec.Command("bash", "-c", rcmd) out, err := cmd.CombinedOutput() if err != nil { log.Println(err.Error()) } log.Println(string(out)) Use os/exec with batch expressions on Windows cmd := exec.Command("cmd", "/c", "ffmpeg -i myfile.mp4 myfile.mp3 && del myfile.mp4") out, err := cmd.CombinedOutput() if err != nil { log.Println(err.Error()) } log.Println(string(out)) Fix local language issues in Windows CMD with os/exec cmd := exec.Command("cmd", "/c", "chcp 65001 && netsh WLAN show drivers") out, err := cmd.CombinedOutput() if err != nil { log.Println(err.Error()) } log.Println(string(out)) When using this method, remember to remove the first line of output (the chcp response) before further processing.

Friday, November 12, 2021 Read

Uncle Joe teaches Elastic - 30 - Elasticsearch optimization tips (4/4) - Shard optimization management

Uncle Joe teaches Elastic - 30 - Elasticsearch optimization tips (4/4) - Shard optimization management Planning considerations During search, each shard uses one thread. Too many shards can slow things down. A node has multiple thread pools by function. The search (count/search/suggest) pool size is int((# of allocated processors * 3) / 2) + 1 and the default queue_size is 1000. The write (index/delete/update/bulk) pool size is # of allocated processors and the default queue_size is also 1000. (Official docs - Thread pools)

Wednesday, November 10, 2021 Read

Regex for Markdown Syntax

Regex for Markdown Syntax basic-syntax # Headings headerOne = `(#{1}\s)(.*)` headeTwo = `(#{2}\s)(.*)` headerThree = `(#{3}\s)(.*)` headerFour = `(#{4}\s)(.*)` headerFive = `(#{5}\s)(.*)` headerSix = `(#{6}\s)(.*)` # Bold and Italic Text boldItalicText = `(\*|\_)+(\S+)(\*|\_)+` # Links linkText = `(\[.*\])($(http)(?:s)?(\:\/\/).*$)` # Images imageFile = `(\!)(\[(?:.*)?\])($.*(\.(jpg|png|gif|tiff|bmp))(?:(\s\"|\')(\w|\W|\d)+(\"|\'))?$` # Unordered List listText = `(^(\W{1})(\s)(.*)(?:$)?)+` # Numbered Text numberedListText = `(^(\d+\.)(\s)(.*)(?:$)?)+` # Block Quotes blockQuote = `((^(\>{1})(\s)(.*)(?:$)?)+` # Inline Code inlineCode = "(\\`{1})(.*)(\\`{1})" # Code Block codeBlock = "(\\`{3}\\n+)(.*)(\\n+\\`{3})" # Horizontal Line horizontalLine = `(\=|\-|\*){3}` # Email Text emailText = `(\<{1})(\S+@\S+)(\>{1})` # TABLES tableText = `(((\|)([a-zA-Z\d+\s#!@'"():;\\\/.\[\]\^<={$}>?(?!-))]+))+(\|))(?:\n)?((\|)(-+))+(\|)(\n)((\|)(\W+|\w+|\S+))+(\|$)`

Friday, October 29, 2021 Read