activerecord-analyze

activerecord-analyze adds an analyze method to Active Record query objects. It executes EXPLAIN ANALYZE on a query SQL.

You can check out this blog post for more info on how to debug and fix slow queries in Rails apps - https://pawelurbanek.com/slow-rails-queries.

forest-spring-boot-starter

What is Forest?

Forest is an open source Java HTTP client framework. It can bind all HTTP request information (including URL, Header, Body and other information) to your custom Interface method, and send HTTP by calling the local interface method.

Add or remove control-plane,master node into the exist kubernetes (K8S) cluster

This still be the easiest with Kubespray.

Kubespray

Kubespray allows you to deploy a production-ready Kubernetes cluster (using Ansible or Vagrant) and since v2.3 can work together with Kubernetes kubeadm.

Vagrant up AlmaLinux OS 8

This article is about to run AlmaLinux OS 8 on VirtualBox with Vagrant.

GNOME on Fedora Cloud

GNOME (/ɡəˈnoʊm, ˈnoʊm/), originally an acronym for GNU Network Object Model Environment, is a free and open-source desktop environment for Linux operating systems.

Fedora Cloud Base images are for creating general purpose virtual machines (VMs). You can use the Qcow 2 image for use with Openstack or the compressed raw image. If you are not sure what to use, try the raw image.

Fedora is always free for anyone to use, modify, and distribute. It is built and used by people across the globe who work together as a community.

Terraform Harbor Examples

Harbor is an open source registry that secures artifacts with policies and role-based access control, ensures images are scanned and free from vulnerabilities, and signs images as trusted. Harbor, a CNCF Graduated project, delivers compliance, performance, and interoperability to help you consistently and securely manage artifacts across cloud native compute platforms like Kubernetes and Docker.

Examples about using Terraform Harbor Provider to manage Harbor projects and users.

kubeplay

kubeplay is a tool for offline deployment of kuberneres clusters based on kubespray.

Feature

• All dependencies included, installing offline with one single command

• amd64 and arm64 CPU architectures supported

• Validity of certificate generated by kubeadm extended to 10 years

• No docker dependency, seamless migrating container runtime to containerd

• Ideal for toB privatized deployment scenarios as all rpm/deb packages (e.g. storage client) needed by bootstraping cluster can be installed offline

• Multi-cluster deployment supported, deploying a new kubernetes cluster with Job Pods within kubernetes cluster

• Offline installer built with GitHub Actions, no charge, 100% open source 100% free

compose

Running nginx and registry with nerdctl - https://github.com/containerd/nerdctl compose on deploy node where deployment tool would run, which provide offline resource download and image distribution services.

kubespray

Using kubespray - https://github.com/kubernetes-sigs/kubespray which come from kubernetes community as a cluster deployment executor, needed resources during deployment will fetched from compose node.

How to deploy

Download

You can download the package matching your platform from the releases page k8sli/kubeplay/releases - https://github.com/k8sli/kubeplay/releases on GitHub, then copy it to deploy node.

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kubeplay-v0.1.0-alpha.3-centos-7.sha256sum.txt # checksum file
kubeplay-v0.1.0-alpha.3-centos-7-amd64.tar.gz  # for  CentOS 7 amd64
kubeplay-v0.1.0-alpha.3-centos-7-amd64.tar.gz  # for CentOS 7 arm64

Configuration

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$ tar -xpf kubeplay-x.y.z-xxx-xxx.tar.gz

$ cd kubeplay

$ cp config-sample.yaml config.yaml

$ vi config.yaml

The config.yaml configuration file is divided into the following sections：

• compose：config for nginx and registry on current deploy node

• kubespray：kubespray deployment config

• invenory：ssh config for nodes of kubernetes cluster

• default：default config values

compose

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compose:
  # Compose bootstrap node ip, default is local internal ip
  internal_ip: 172.20.0.25
  # Nginx http server bind port for download files and packages
  nginx_http_port: 8080
  # Registry domain for CRI runtime download images
  registry_domain: kube.registry.local

kubespray

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kubespray:
  # Kubernetes version by default, only support v1.20.6
  kube_version: v1.21.3
  # For deploy HA cluster you must configure a external apiserver access ip
  external_apiserver_access_ip: 127.0.0.1
  # Set network plugin to calico with vxlan mode by default
  kube_network_plugin: calico
  #Container runtime, only support containerd if offline deploy
  container_manager: containerd
  # Now only support host if use containerd as CRI runtime
  etcd_deployment_type: host
  # Settings for etcd event server
  etcd_events_cluster_setup: true
  etcd_events_cluster_enabled: true

inventory

inventory is the ssh login configuration for nodes of kubernetes cluster , supporting yaml, json, and ini formats.

yaml format

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# Cluster nodes inventory info
inventory:
  all:
    vars:
      ansible_port: 22
      ansible_user: root
      ansible_ssh_pass: Password
      # Remmber to put your id_rsa into ./kubespray/config dir.
      # ansible_ssh_private_key_file: /kubespray/config/id_rsa
    hosts:
      node1:
        ansible_host: 172.20.0.21
      node2:
        ansible_host: 172.20.0.22
      node3:
        ansible_host: 172.20.0.23
      node4:
        ansible_host: 172.20.0.24
    children:
      kube_control_plane:
        hosts:
          node1:
          node2:
          node3:
      kube_node:
        hosts:
          node1:
          node2:
          node3:
          node4:
      etcd:
        hosts:
          node1:
          node2:
          node3:
      k8s_cluster:
        children:
          kube_control_plane:
          kube_node:
      gpu:
        hosts: {}
      calico_rr:
        hosts: {}

default value

The following default parameters are not recommended to be modified without special requirements, just leave them as default. Unmodified ntp_server value will be overrided by internal_ip from compose section; registry_ip and offline_resources_url are automatically generated based on the parameters in compose section thus not need to modify.

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default:
  # NTP server ip address or domain, default is internal_ip
  ntp_server:
    - internal_ip
  # Registry ip address, default is internal_ip
  registry_ip: internal_ip
  # Offline resource url for download files, default is internal_ip:nginx_http_port
  offline_resources_url: internal_ip:nginx_http_port
  # Use nginx and registry provide all offline resources
  offline_resources_enabled: true
  # Image repo in registry
  image_repository: library
  # Kubespray container image for deploy user cluster or scale
  kubespray_image: "kubespray"
  # Auto generate self-signed certificate for registry domain
  generate_domain_crt: true
  # For nodes pull image, use 443 as default
  registry_https_port: 443
  # For push image to this registry, use 5000 as default, and only bind at 127.0.0.1
  registry_push_port: 5000
  # Set false to disable download all container images on all nodes
  download_container: false

  # enable support hubble in cilium
  cilium_enable_hubble: false
  # install hubble-relay, hubble-ui
  cilium_hubble_install: false
  # install hubble-certgen and generate certificates
  cilium_hubble_tls_generate: false
  # Kube Proxy Replacement mode (strict/probe/partial)
  cilium_kube_proxy_replacement: probe

Usages

Deploy a new cluster

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$ bash install.sh

Add node to existing cluster

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$ bash install.sh add-node $NODE_NAMES

Delete node from cluster

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$ bash install.sh remove-node $NODE_NAME

Remove cluster

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$ bash install.sh remove-cluster

Remove all components

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$ bash install.sh remove

FAQs

msg: ‘Failed to download metadata for repo ‘‘docker-ce’’: Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried’

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# yum update
Yum offline resources
Errors during downloading metadata for repository 'docker-ce':
  - Status code: 404 for http://192.168.8.120:8080/centos/8/os/x86_64/repodata/repomd.xml (IP: 192.168.8.121)
Error: Failed to download metadata for repo 'docker-ce': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

Copy offline centos/8 resources to resolve it.

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# wget -c https://github.com/k8sli/kubeplay/releases/download/v0.1.0-alpha.3/kubeplay-v0.1.0-alpha.3-centos-7-amd64.tar.gz

# tar -xvf kubeplay-v0.1.0-rc.2-centos-8-amd64.tar.gz

# cp -r kubeplay-v0.1.0-rc.2-centos-8-amd64/resources/nginx/centos/8 kubeplay-v0.1.0-rc.2-centos-7-amd64/resources/nginx/centos

References

[1] k8sli/kubeplay: Deploy kubernetes by kubespray in offline - https://github.com/k8sli/kubeplay

[2] Deploy a Production Ready Kubernetes Cluster | Readme - https://kubespray.io/

[3] Ansible is Simple IT Automation - https://www.ansible.com/

[4] Kubernetes - https://kubernetes.io/

[5] containerd/nerdctl: Docker-compatible CLI for containerd, with support for Compose - https://github.com/containerd/nerdctl

kubeasz

kubeasz is committed to providing tools for rapid deployment of high-availability k8s clusters, and also strives to become a reference book for k8s practice and use; deployment based on binary mode and automation using ansible-playbook; not only provides one-click installation scripts, but also can be divided according to the installation guide Step by step to install each component.

almalinux-deploy - An EL (CentOS) to AlmaLinux migration tool.