Linux Systemd Cheat Sheet Useful

07/26/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Systemd Cheat Sheet in Linux
3 Logs with systemd
4 Introspection with systemd
5 Services
6 Targets (runlevels)
7 FAQ Section
8 External Resources
9 Conclusion

Introduction

In this tutorial, I write about the Systemd cheat sheet useful in Linux. Systemd provides a system and service that runs at PID 1. It tracks logged-in users and runs containers virtual machines and more.

The Linux Systemd Cheat Sheet is a handy guide that provides quick and easy-to-understand information about Systemd. Systemd is a system and service manager for Linux operating systems, and this cheat sheet is designed to help users navigate and utilize its features efficiently.

Whether you’re a beginner or an experienced Linux user, this cheat sheet covers essential commands and functions related to Systemd. From starting and stopping services to managing system processes, the cheat sheet is a valuable resource for anyone looking to streamline their Linux system management tasks.

With the Linux Systemd Cheat Sheet, you can quickly reference key Systemd commands, making it easier to troubleshoot issues, configure services, and optimize system performance. This user-friendly guide aims to empower Linux users with the knowledge they need to navigate Systemd effectively, ensuring a smoother and more efficient system administration experience.

Systemd Cheat Sheet in Linux

Logs with systemd

The content	Command Line
View all system logs	journalctl
List boot numbers	journalctl –list-boots
View logs for unit ssh	journalctl –unit ssh
View system logs from the most recent	journalctl -xe

For example the picture below

Introspection with systemd

The content	Command Line
show unit file settings	systemctl show sshd
Show contents of the unit file	systemctl cat sshd
Show whether the unit is active	systemctl is-active sshd
Show whether the unit has failed	systemctl is-failed sshd
Edit unit file configuration	sudo systemctl edit sshd
Restart daemon	sudo systemctl daemon-reload

Services

The content	Command Line
Start service nginx	systemctl start nginx
Stop service nginx	systemctl stop nginx
Show status of service nginx	systemctl status nginx
Start nginx now and at system startup	systemctl enable –now nginx
At system startup, start (enable) nginx	systemctl enable nginx
At system startup, do not start nginx	systemctl disable nginx
Show whether service nginx is enabled	systemctl is-enabled nginx
Prevent service from starting (mask)	systemctl mask nginx
Unmask service, allowing it to be started	systemctl unmask nginx
List all available services	systemctl list-unit-files –-type service

For example as below

Targets (runlevels)

Targets, also known as runlevels in Linux, play a crucial role in managing the system’s state and functionality. Think of targets as different modes or scenarios your computer can operate in, each with a specific set of services and processes.

In simpler terms, runlevels help define what your computer is supposed to do at different stages – be it during startup, regular operation, or shutdown. For instance, runlevel 3 might focus on a multi-user environment with networking capabilities, while runlevel 5 could include a graphical user interface for a more user-friendly experience.

These runlevels or targets allow users to customize and control the behavior of their Linux system based on their needs. Whether you’re setting up a server that doesn’t require a graphical interface or a desktop environment for everyday use, understanding and configuring runlevels is essential for tailoring your Linux experience.

The content	Command line
List all available targets	systemctl list-unit-files –-type target
Show dependencies of a target	systemctl list-dependencies nginx
Show default boot target	systemctl get-default
Boot to a text console	systemctl set-default multi-user
Boot to a graphical desktop	systemctl set-default graphical

FAQ Section

1. What is the difference between `systemctl` and `journalctl`?

systemctl manages services, units, and targets, while journalctl is used to view logs maintained by Systemd.

2. Can Systemd work alongside other init systems?

Yes, but it’s not recommended as conflicts can arise. Most modern Linux distributions have fully transitioned to Systemd.

3. How do I troubleshoot failed services?

Use:

systemctl status <service-name>

Then, check logs with:

journalctl -u <service-name>

External Resources

Conclusion

You should utilize the helpful Systemd Cheat Sheet in Linux. The cheat sheet includes fundamental systemd commands, and there are even more advanced features and options to explore. For detailed information about specific commands or options, you can check the systemd documentation or man pages (man systemctl). I hope you find this information useful. Thank you for visiting the DevopsRoles page!”

Kubernetes

Kubernetes day one

07/19/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 Method installs for Kubernetes.
2 Install Kubectl on Windows
3 Install Minikube on Windows
4 K8S PODS

#Introduction

In this tutorial, We study together K8s (Kubernetes). Let go of Kubernetes day one.

Method installs for Kubernetes.
Use Managed Kubernetes service from CSP.
Install and configure Kubectl for Linux and macOS.
Configuring Kubernetes in Minikube Windows or Linux.
Minikube install commands.
Create the First POD configuration in YAML.
How to generate Pod Manifests via CLI.

Method installs for Kubernetes.

There are multiple methods to get started with a full Kubernetes Environment.

Use the Managed Kubernetes Service.
Install and configure Kubernetes Manually
Use Minikube

Managed Kubernetes Service.

Provides like: AWS, GCP, IBM, and others providers.

Minikube

It’s a tool that makes it easy to run Kubernetes locally.

Minikube run a single node K8s cluster on VM on your laptop. You can try out or develop with it.

Install and configure Kubernetes Manually

It’s the Hard Way. You install and configure components of K8s.

Install Kubectl on Windows

it allows running commands against K8s clusters.

Kubectl to deploy applications, manage cluster resources, and view logs. Link here.

Download Kubectl here

Add path environment variable for K8s

Confirm kubectl command on Windows.

Install Minikube on Windows

Link here.

For example below:

From a terminal start your cluster.

K8S PODS

Kubernetes Pod is a group of one or more application containers that share resources.

A Pod runs on a Node.
Each Node is managed by the Master.
A Node has multiple pods.
A Node is a worker machine in K8s.

The command same docker vs K8s

docker run –name webserver nginx	kubectl run webserver –image=nginx
docker exec -it webserver bash	kubectl exec -it webserver — bash
docker stop webserver docker rm webserver	kubectl delete pod webserver

Updating later!

Docker

Deploy the Latest Portainer Release

07/15/2022 HuuPV Leave a comment

Portainer frequently releases updates. You can not simply login to your Portainer container upgrade button, in this tutorial, How to Deploy the Latest Portainer Release.

Table of Contents

1 Backup Portainer container.
2 Deploy the Latest Portainer Release
3 Restore a Backup for the Portainer container.
4 Conclusion

Backup Portainer container.

I’ll back up the current Portainer deployment.
Login with admin user and click Settings in the left navigation as in the picture below:

I will download the backup file to local storage and save a .tar.gz

Stop/Remove the Current Portainer Container

docker ps -a|grep portainer
docker stop ID
docker rm ID

Where ID is the ID of the Portainer container.

For example, The output terminal is as below:

Deploy the Latest Portainer Release

See install Portainer docker here. I used portainer_data for persistent storage.

First, You need to pull down the Portainer latest.

docker pull portainer/portainer-ce:latest

Deploy Portainer with the command line as below

docker run -d -p 8000:8000 -p 9000:9000 --name=portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce

Open a web browser and access to link: http://SERVER:9000

Restore a Backup for the Portainer container.

You need to deploy a fresh instance of Portainer with an empty data volume and choose the Restore Portainer from the backup option during setup. Click Select file and navigate to the .tar.gz file you downloaded earlier. After selecting the file, click Restore Portainer.

Conclusion

You have to deploy Portainer Docker. Please note that these steps provide a basic overview of deploying Portainer.

For a production environment, it’s essential to consider security measures and other best practices. It’s always recommended to consult Portainer’s official documentation for more detailed instructions specific to the latest release and any additional configuration options.

I hope will this your helpful. Thank you for reading the DevopsRoles page!

Linux

How to install CouchDB on Rocky Linux 8: A Comprehensive Guide

07/10/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Install CouchDB on Rocky Linux 8
- 2.1 Install CouchDB
3 YouTube: Step-by-Step Guide: Installing CouchDB on Rocky Linux 8
- 3.1 Verify the installation.
4 Configuration of CouchDB on Rocky Linux 8
5 Creating a Database
6 Conclusion

Introduction

In this tutorial, How to Install CouchDB on Rocky Linux Server. We’ll cover each step, from updating your system and installing necessary dependencies to configuring CouchDB for optimal performance. By the end of this guide, you will have a fully functional CouchDB instance running on your Rocky Linux server, ready to handle your database needs with reliability and efficiency.

CouchDB is a NoSQL database.
CouchDB stores and presents data in JavaScript Object Notation.

Install CouchDB on Rocky Linux 8

Update the System

$ sudo yum update

Install “epel-release” repository.

$ sudo yum install epel-release

Enable the Apache CouchDB package repository.

$ sudo vi /etc/yum.repos.d/apache-couchdb.repo

The content is as below:

[bintray--apache-couchdb-rpm]
name=bintray--apache-couchdb-rpm
baseurl=http://apache.bintray.com/couchdb-rpm/el$releasever/$basearch/
gpgcheck=0
repo_gpgcheck=0
enabled=1

You want to install Standalone or Cluster Mode. I will use standalone mode.

Install CouchDB

How to fix the error code below:

[vagrant@localhost ~]$ sudo yum install couchdb
bintray--apache-couchdb-rpm                                                                                                                                                      170  B/s | 166  B     00:00
Errors during downloading metadata for repository 'bintray--apache-couchdb-rpm':
  - Status code: 502 for http://apache.bintray.com/couchdb-rpm/el8/x86_64/repodata/repomd.xml (IP: 34.215.50.170)
Error: Failed to download metadata for repo 'bintray--apache-couchdb-rpm': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

You need to delete the repo and add the repo for “couchdb.repo” as below:

$ sudo rm /etc/yum.repos.d/apache-couchdb.repo
$ sudo yum-config-manager --add-repo https://couchdb.apache.org/repo/couchdb.repo

YouTube: Step-by-Step Guide: Installing CouchDB on Rocky Linux 8

Now, You install the Couchdb server.

$ sudo yum install couchdb

The output terminal is the picture below:

Verify the installation.

Start services

# systemctl start couchdb
# systemctl enable couchdb
# systemctl status couchdb

Firewalld setting allows port 5984

$ sudo firewall-cmd --zone=public --permanent --add-port=5984/tcp
$ sudo systemctl start firewalld

The CouchDB server will run on localhost:5984

Configuration of CouchDB on Rocky Linux 8

CouchDB’s configuration files are located in the /opt/couchdb/etc/ directory.

Open the file

$ sudo vi /opt/couchdb/etc/local.ini

uncommenting the line just below

[admins]
admin = mypassword

Uncomment the port and bind-address values.

[chttpd]
port = 5984
bind_address = 0.0.0.0

Save the changes and exit the configuration file.

Creating a Database

Access CouchDB Web Interface at http://127.0.0.1:5984/_utils/ with your user credentials and create a new database with CouchDB.

By default, CouchDB listens on port 5984.

Conclusion

You have to Install CouchDB on Rocky Linux 8. CouchDB should now be installed and running on your Rocky Linux 8 system. Remember to secure your CouchDB installation and configure any necessary authentication and access controls based on your requirements. I hope this will be helpful for you. Thank you for reading the DevopsRoles page!

Kubernetes

How to install kubernetes on ubuntu

06/28/2022 HuuPV Leave a comment

To install Kubernetes on Ubuntu, you can use the kubeadm tool, which simplifies the process of setting up a cluster. Here’s a step-by-step guide on how to install Kubernetes on Ubuntu.

Table of Contents

0.1 Kubernetes Requirements
0.2 1. Update Ubuntu Server
0.3 2. Install Docker on Ubuntu Server

1 3.How to install Kubernetes on Ubuntu server.
2 Join the worker node to Cluster.
3 Conclusion

Kubernetes Requirements

Master Node.

Worker Node 1.

The host OS is Ubuntu Server.

1. Update Ubuntu Server

It is always an updated system package. use the command line below:

$ sudo apt update

2. Install Docker on Ubuntu Server

$ sudo apt install curl -y
$ curl -fsSL https://get.docker.com -o get-docker.sh
$ sh get-docker.sh
$ sudo usermod -aG docker $USER
$ docker --version

Repeat on all other nodes.

3.How to install Kubernetes on Ubuntu server.

Use the command line to install K8s as below.

$ sudo apt-get install -y apt-transport-https ca-certificates curl
$ sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

Repeat for each server node.

4. Add software repositories

k8s are not included in the default repositories. Use the command line below:

$ echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
$ sudo apt-get update

Repeat for each server node.

5. Install the tool for Kubernetes

A tool that helps to initialize a cluster using Kubernetes Admin or Kubeadm. Kubelet is the worker package, which runs on all nodes and starts containers. Use the command line below

$ sudo apt-get install -y kubeadm kubelet kubectl
$ sudo apt-mark hold kubelet kubeadm kubectl

Repeat for each server node.

6. Disabling swap memory on each server

$ sudo swapoff -a

7. Setting a unique hostname for each server node.

Decide which server to set as the primary node.

$ sudo hostnamectl set-hostname k8s-master

Next, Set a worker node hostname

$ sudo hostnamectl set-hostname k8s-node1

If you add a worker node, set a unique hostname on each one.

8. Initialize Kubernetes on the master node

On the master node, Run the command below:

$ sudo kubeadm init --apiserver-advertise-address=192.168.56.11 --pod-network-cidr=10.100.0.0/16

The output terminal is as below:

vagrant@k8s-master:~$ sudo kubeadm init --apiserver-advertise-address=192.168.56.11 --pod-network-cidr=10.100.0.0/16
[init] Using Kubernetes version: v1.24.2
[preflight] Running pre-flight checks
        [WARNING SystemVerification]: missing optional cgroups: blkio
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.56.11]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.11 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.11 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 4.501962 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node k8s-master as control-plane by adding the labels: [node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule node-role.kubernetes.io/control-plane:NoSchedule]
[bootstrap-token] Using token: 8ke6fa.3c5ll272057418qj
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.56.11:6443 --token 8ke6fa.3c5ll272057418qj \
        --discovery-token-ca-cert-hash sha256:4e69979a597f673781606eb7ab6bed5ccb741f46756b17f196b9cd76d3b51053

This is used to join the worker nodes to the cluster. We will create a directory for the cluster.

$ mkdir -p $HOME/.kube 
$ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config 
$ sudo chown $(id -u):$(id -g) $HOME/.kube/config

9. Deploy the pod network to the cluster.

A pod network allows communication between different nodes in the cluster. For example, Use the flannel virtual network. Use the command line below

$ sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Verify working and communicating

# kubectl get all -A

Join the worker node to Cluster.

The syntax:

kubeadm join --token <token> <control-plane-host>:<control-plane-port> --discovery-token-ca-cert-hash sha256:<hash>

Use kubeadm join command on each worker node to join it to the cluster.

$ sudo kubeadm join 192.168.56.11:6443 --token 8ke6fa.3c5ll272057418qj \
        --discovery-token-ca-cert-hash \
sha256:4e69979a597f673781606eb7ab6bed5ccb741f46756b17f196b9cd76d3b5105

Waiting minutes, You can check the status of the nodes. Switch to the Master node and run the command line as below:

kubectl get nodes

Conclusion

You have successfully installed Kubernetes on Ubuntu. I hope this guide proves to be helpful for you in navigating the installation process. Thank you for choosing to read the DevopsRoles page! For more detailed instructions on how to install Kubernetes on Ubuntu, please refer to our comprehensive guide on installing Kubernetes on Ubuntu.

Docker

Docker deploy Joomla

06/12/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
- 1.1 Requirements
2 Docker Joomla
3 Deploy the database
4 How to deploy Joomla
- 4.1 Access the web-based installer
5 Via Youtube
6 Conclusion

Introduction

Docker has become an essential tool in the DevOps world, simplifying the deployment and management of applications. Using Docker to deploy Joomla – one of the most popular Content Management Systems (CMS) – offers significant advantages. In this article, we will guide you through each step to Docker deploy Joomla, helping you leverage the full potential of Docker for your Joomla project.

Requirements

Have installed Docker on your system.
The host OS is Ubuntu Server.

To deploy Joomla using Docker, you’ll need to follow these steps:

Docker Joomla

Create a new Docker joomla network

docker network create joomla-network

Check Joomla network is created.

Next, pull Joomla and MySQL images as command below:

docker pull mysql:5.7
docker pull joomla

Create the MySQL volume

docker volume create mysql-data

Deploy the database

docker run -d --name joomladb  -v mysql-data:/var/lib/mysql --network joomla-network -e "MYSQL_ROOT_PASSWORD=PWORD_MYSQL" -e MYSQL_USER=joomla -e "MYSQL_PASSWORD=PWORD_MYSQL" -e "MYSQL_DATABASE=joomla" mysql:5.7

Where PWORD_MYSQL is a unique/strong password

How to deploy Joomla

create a volume to hold the Joomla data as command below:

docker volume create joomla-data

docker run -d --name joomla -p 80:80 -v joomla-data:/var/www/html --network joomla-network -e JOOMLA_DB_HOST=joomladb -e JOOMLA_DB_USER=joomla -e JOOMLA_DB_PASSWORD=PWORD_MYSQL joomla

Access the web-based installer

Open the web browser to http://SERVER:PORT, where SERVER is either the IP address or domain of the hosting server, and PORT is the external port.

Follow the Joomla setup wizard to configure your Joomla instance.

Via Youtube

Conclusion

Deploying Joomla with Docker not only simplifies the installation and configuration process but also enhances the management and scalability of your application. With the detailed steps provided in this guide, you can confidently deploy and manage Joomla on the Docker platform. Using Docker saves time and improves the performance and reliability of your system. Start today to experience the benefits Docker brings to your Joomla project. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Kubernetes

Setup Kubernetes Cluster with K3s

06/05/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Setup Kubernetes Cluster with K3s
- 2.1 Download the Rancher binary
- 2.2 How to manage your cluster
3 Add nodes to a K3s cluster
4 Conclusion

Introduction

In this tutorial, How to setup Kubernetes Cluster with K3s. It is a lightweight Kubernetes distribution developed by Rancher. K3s consume fewer resources than traditional distributions. It’s easy to set up and manage Kubernetes Cluster.

To set up a Kubernetes cluster using K3s, you can follow these steps:

Setup Kubernetes Cluster with K3s

First, You need to get a Linux machine.

Start by provisioning the servers that will be part of your Kubernetes cluster.

You can use virtual machines or bare-metal servers. Ensure that the servers have a compatible operating system (such as Ubuntu, CentOS, or RHEL).

Download the Rancher binary

Link download here. or you use the wget command or curl command to get download it.

wget https://github.com/k3s-io/k3s/releases/download/v1.23.5%2Bk3s1/k3s

make the binary executable.

chmod +x k3s

The output terminal is as below:

vagrant@controller:~$ wget https://github.com/k3s-io/k3s/releases/download/v1.23.5%2Bk3s1/k3s
--2022-06-05 08:49:28--  https://github.com/k3s-io/k3s/releases/download/v1.23.5%2Bk3s1/k3s
Resolving github.com (github.com)... 20.205.243.166
Connecting to github.com (github.com)|20.205.243.166|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://objects.githubusercontent.com/github-production-release-asset-2e65be/135516270/88b18d50-2447-4216-b672-fdf17488cb41?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20220605%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20220605T084929Z&X-Amz-Expires=300&X-Amz-Signature=54b2aa58e831f8f8d179189c940eb5c38b4df7d4e3e33c18c9376b446f029742&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=135516270&response-content-disposition=attachment%3B%20filename%3Dk3s&response-content-type=application%2Foctet-stream [following]
--2022-06-05 08:49:28--  https://objects.githubusercontent.com/github-production-release-asset-2e65be/135516270/88b18d50-2447-4216-b672-fdf17488cb41?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20220605%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20220605T084929Z&X-Amz-Expires=300&X-Amz-Signature=54b2aa58e831f8f8d179189c940eb5c38b4df7d4e3e33c18c9376b446f029742&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=135516270&response-content-disposition=attachment%3B%20filename%3Dk3s&response-content-type=application%2Foctet-stream
Resolving objects.githubusercontent.com (objects.githubusercontent.com)... 185.199.108.133, 185.199.109.133, 185.199.110.133, ...
Connecting to objects.githubusercontent.com (objects.githubusercontent.com)|185.199.108.133|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 62468096 (60M) [application/octet-stream]
Saving to: ‘k3s’

k3s                                100%[==============================================================>]  59.57M  4.95MB/s    in 24s

2022-06-05 08:49:53 (2.46 MB/s) - ‘k3s’ saved [62468096/62468096]

vagrant@controller:~$ ls -l
total 61004
-rw-rw-r-- 1 vagrant vagrant 62468096 Mar 31 01:05 k3s
vagrant@controller:~$ chmod +x k3s

Start the K3s Server.

sudo ./k3s server

Check your Kubernetes cluster

sudo ./k3s kubectl get nodes

The output terminal is as below:

How to manage your cluster

You can run kubectl commands through the k3s binary. K3s provides a built-in kubectl utility.

For example, To drain the node you created.

sudo ./k3s kubectl drain your-hostname

Or use kubectl cordon a node with the command below:

sudo ./k3s kubectl cordon your-hostname

Add nodes to a K3s cluster

We created a cluster with just one node with the step above. If you want add 1 node to your cluster.

On Master:

first, you determine the node token value of your server. get the token value with the command below:

sudo cat /var/lib/rancher/k3s/server/node-token

For example, the Token values the output as below:

K10c94d11d4970c4ac58973c98ee32c9c1c4cb4fc30d81adfaf3ddf405ba1c48b49::server:7b1dcfc180415f105af019717027e77c

On Worker

Install k3s agent

export K3S_NODE_NAME=node1
export K3S_URL="https://192.168.56.11:6443"
export K3S_TOKEN=K10c94d11d4970c4ac58973c98ee32c9c1c4cb4fc30d81adfaf3ddf405ba1c48b49::server:7b1dcfc180415f105af019717027e77c
curl -sfL https://get.k3s.io | sh -s -

Then, the Additional node run command below:

sudo k3s agent --server https://myserver:6443 --token K3S_TOKEN

Repeat this process to add as many nodes as you want to your cluster.

The result, of the Master

Conclusion

You have setup Kubernetes cluster using K3s. You can now use kubectl it to deploy and manage your applications on the cluster.

Further, you can do with k8s k3s such as customize networking or logging, change the container runtime, and set up certificates. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Docker

Create docker secret and deploy a service

05/30/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction
0.2 Requirements

1 How to create a secret
2 create a service that uses the secret
3 Conclusion

#Introduction

In this tutorial, How to create docker secret and deploy a service. Docker secrets encrypt things like passwords and certificates within a service and container.

Requirements

Have installed Docker on your system.
A full Docker Swarm cluster.

How to create a secret

We’ll use the command printf and pipe the output to the docker command to create a secret called test_secret. As command below:

printf "My secret secret" | docker secret create test_secret -

To check the result with the command below

docker secret ls

The output as below:

vagrant@controller:~$ docker secret ls
ID                          NAME          DRIVER    CREATED          UPDATED
txrthzah1vnl4kyrh282j39ft   test_secret             24 seconds ago   24 seconds ago

create a service that uses the secret

To deploy that service, using the test_secret secret, the command looks something like this:

docker service  create --name redis --secret test_secret redis:alpine

Verify the service is running as the command below

docker service ps redis

The output is as below:

vagrant@controller:~$ docker service ps redis
ID             NAME      IMAGE          NODE         DESIRED STATE   CURRENT STATE            ERROR     PORTS
y6249s3xftxa   redis.1   redis:alpine   controller   Running         Running 33 seconds ago

Verify the service has access to the secret as below

docker container exec $(docker ps --filter name=redis -q) ls -l /run/secrets

The output is as below:

vagrant@controller:~$ docker container exec $(docker ps --filter name=redis -q) ls -l /run/secrets
total 4
-r--r--r--    1 root     root            16 May 30 13:50 test_secret

Finally, you can view the contents of the secret with the command:

docker container exec $(docker ps --filter name=redis -q) cat /run/secrets/test_secret

The output is as below:

My secret secret

If you commit the container, the secret is no longer available.

docker commit $(docker ps --filter name=redis -q) committed_redis

Verify the secret is no longer available with the command below:

docker run --rm -it committed_redis cat /run/secrets/test_secret

You can then remove access to the secret with the command:

docker service update --secret-rm test_secret redis

Conclusion

You have to Create docker secret and deploy a service. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Ansible

Using Ansible with Testinfra test infrastructure

05/12/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Ansible Testinfra test infrastructure
- 2.1 Install Testinfra
- 2.2 For example, A simple test script
3 Testinfra and Ansible
4 Conclusion

Introduction

In this tutorial, How to ansible testinfra test infrastructure. You can write unit tests in Python to test the actual status of your target servers.

Ansible Testinfra is a testing framework that allows you to write tests for your Ansible playbooks and roles. It is built on top of the popular Python testing framework pytest and provides a simple way to test the state of your systems after running Ansible playbooks.

Testinfra is a powerful library for writing tests to verify an infrastructure’s state. It is a Python library and uses the powerful pytest test engine.

Ansible Testinfra test infrastructure

Install Testinfra

Method 1: Use pip ( Python package manager ) to install Testinfra and a Python virtual environment.

python3 -m venv ansible
source ansible/bin/activate
(ansible) $ pip install testinfra

Method 2: Testinfra is also available in the package repositories of Fedora and CentOS using the EPEL repository. For example, install on CentOS 7 as command below:

$ yum install -y epel-release
$ yum install -y python-testinfra

For example, A simple test script

I create test.py with the content below:

import testinfra

def test_os_release(host):
    assert host.file("/etc/os-release").contains("centos")

def test_sshd_active(host):
    assert host.service("sshd").is_running is True

To run these tests on your local machine, execute the following command:

(ansible)$ pytest test.py

Testinfra and Ansible

Use pip to install the Ansible package.

pip install ansible

Here is the resulting output:

(ansible) [vagrant@ansible ~]$ pip install ansible
Collecting ansible
  Downloading ansible-4.10.0.tar.gz (36.8 MB)
     |████████████████████████████████| 36.8 MB 6.9 MB/s
  Preparing metadata (setup.py) ... done
Collecting ansible-core~=2.11.7
  Downloading ansible-core-2.11.11.tar.gz (7.1 MB)
     |████████████████████████████████| 7.1 MB 9.6 MB/s
  Preparing metadata (setup.py) ... done
Collecting jinja2
  Downloading Jinja2-3.0.3-py3-none-any.whl (133 kB)
     |████████████████████████████████| 133 kB 10.4 MB/s
Collecting PyYAML
  Downloading PyYAML-6.0-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl (603 kB)
     |████████████████████████████████| 603 kB 8.7 MB/s
Collecting cryptography
  Downloading cryptography-37.0.2-cp36-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (4.1 MB)
     |████████████████████████████████| 4.1 MB 11.5 MB/s
Requirement already satisfied: packaging in ./ansible/lib/python3.6/site-packages (from ansible-core~=2.11.7->ansible) (21.3)
Collecting resolvelib<0.6.0,>=0.5.3
  Downloading resolvelib-0.5.4-py2.py3-none-any.whl (12 kB)
Collecting cffi>=1.12
  Downloading cffi-1.15.0-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl (405 kB)
     |████████████████████████████████| 405 kB 10.7 MB/s
Collecting MarkupSafe>=2.0
  Downloading MarkupSafe-2.0.1-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl (30 kB)
Requirement already satisfied: pyparsing!=3.0.5,>=2.0.2 in ./ansible/lib/python3.6/site-packages (from packaging->ansible-core~=2.11.7->ansible) (3.0.9)
Collecting pycparser
  Downloading pycparser-2.21-py2.py3-none-any.whl (118 kB)
     |████████████████████████████████| 118 kB 12.3 MB/s
Using legacy 'setup.py install' for ansible, since package 'wheel' is not installed.
Using legacy 'setup.py install' for ansible-core, since package 'wheel' is not installed.
Installing collected packages: pycparser, MarkupSafe, cffi, resolvelib, PyYAML, jinja2, cryptography, ansible-core, ansible
    Running setup.py install for ansible-core ... done
    Running setup.py install for ansible ... done
Successfully installed MarkupSafe-2.0.1 PyYAML-6.0 ansible-4.10.0 ansible-core-2.11.11 cffi-1.15.0 cryptography-37.0.2 jinja2-3.0.3 pycparser-2.21 resolvelib-0.5.4
(ansible) [vagrant@ansible ~]$

Testinfra can directly use Ansible’s inventory file and a group of machines defined in the inventory. For example, inventory hosts are the target server Ubuntu.

(ansible) [vagrant@ansible ~]$ cat hosts
[target-server]
UbuntuServer

We verify the operating system and ensure that SSH is running on the target server.

To test using Testinfra and Ansible, use the following command:

pytest -vv --sudo --hosts=target-server --ansible-inventory=hosts --connection=ansible test.py

The terminal output is as follows:

Conclusion

You have Ansible Testinfra test infrastructure. Ansible and Testinfra are complementary tools that can be used together in an infrastructure provisioning and testing workflow, but they serve different purposes.

Ansible specializes in automation and configuration management, whereas Testinfra is dedicated to testing the infrastructure. I hope you find this information helpful. Thank you for visiting the DevopsRoles page!

Docker

Elastic APM Tool for Application Performance Monitoring

05/05/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 Elastic APM Tool
- 1.1 Running the APM tool
2 Configuration steps on Kibana
3 Conclusion

#Introduction

Elastic APM helps you monitor overall application health and performance. It is part of the Elastic Stack, which includes Elasticsearch, Logstash, and Kibana.

Elastic APM allows you to track and analyze the performance metrics of your applications, identify bottlenecks, and troubleshoot issues.

Prerequisites

Host OS: Ubuntu 21.04
Installed Docker and Docker-compose
elastic-apm-agent Java agent can be downloaded from here.

Elastic APM Tool

How to integrate the application with APM tool: elasticsearch, kibana, and apm-server

We will create a docker-compose file with the content below:

nano docker-compose.yml

The content file as below:

version: '3'
services:
      elasticsearch:
        image: docker.elastic.co/elasticsearch/elasticsearch:6.6.1
        ports:
          - "9200:9200"
      kibana:
        image: docker.elastic.co/kibana/kibana:6.6.1
        ports:
          - "5601:5601"
        depends_on:
          - elasticsearch
      apm-server:
          image: docker.elastic.co/apm/apm-server:6.6.1
          environment:
            - output.elasticsearch.hosts=["elasticsearch:9200"]
          ports:
            - "8200:8200"
          depends_on:
            - elasticsearch

Save and close that file.

Running the APM tool

docker-compose up -d

The result is the picture below:

Now, We will start the application with the javaagent and point to apm-server URL

java -javaagent:/<path-to-jar>/elastic-apm-agent-<version>.jar \
     -Delastic.apm.service_name=my-application \
     -Delastic.apm.server_url=http://localhost:8200 \
     -Delastic.apm.secret_token= \
     -Delastic.apm.application_packages=<base package> \
     -jar <jar name>.jar

Note: apm.application_packages → package where the main class is present

Configuration steps on Kibana

Goto: http://localhost:5601 (http://localhost:5601/)
Click on Add APM
Scroll down and click on Check APM Server Status
Scroll down and click on Check agent status
Click on Load Kibana objects
Launch APM

APM is now ready and integrated with the service.

Conclusion

You have Elastic APM Tool for Application Performance Monitoring.

Elastic APM is a comprehensive tool for monitoring the performance of your applications, providing deep insights into transaction traces, metrics, errors, and code-level details. It helps you identify performance issues, optimize application performance, and deliver a better user experience.

I hope will this your helpful. Thank you for reading the DevopsRoles page!

Introduction

Systemd Cheat Sheet in Linux

Logs with systemd

Introspection with systemd

Services

Targets (runlevels)

FAQ Section

1. What is the difference between systemctl and journalctl?

2. Can Systemd work alongside other init systems?

3. How do I troubleshoot failed services?

External Resources

Conclusion

#Introduction

Method installs for Kubernetes.

Managed Kubernetes Service.

Minikube

Install and configure Kubernetes Manually

Install Kubectl on Windows

Install Minikube on Windows

K8S PODS

Backup Portainer container.

Deploy the Latest Portainer Release

Restore a Backup for the Portainer container.

Conclusion

Introduction

Install CouchDB on Rocky Linux 8

Install CouchDB

YouTube: Step-by-Step Guide: Installing CouchDB on Rocky Linux 8

Verify the installation.

Configuration of CouchDB on Rocky Linux 8

Creating a Database

Conclusion

Kubernetes Requirements

1. Update Ubuntu Server

2. Install Docker on Ubuntu Server

3.How to install Kubernetes on Ubuntu server.

4. Add software repositories

5. Install the tool for Kubernetes

6. Disabling swap memory on each server

7. Setting a unique hostname for each server node.

8. Initialize Kubernetes on the master node

9. Deploy the pod network to the cluster.

Join the worker node to Cluster.

Conclusion

Introduction

Requirements

Docker Joomla

Deploy the database

How to deploy Joomla

Access the web-based installer

Via Youtube

Conclusion

Introduction

Setup Kubernetes Cluster with K3s

Download the Rancher binary

How to manage your cluster

Add nodes to a K3s cluster

Conclusion

#Introduction

Requirements

How to create a secret

create a service that uses the secret

Conclusion

Introduction

Ansible Testinfra test infrastructure

Install Testinfra

For example, A simple test script

Testinfra and Ansible

Conclusion

#Introduction

Elastic APM Tool

Running the APM tool

Configuration steps on Kibana

Conclusion

Devops Tutorial

1. What is the difference between `systemctl` and `journalctl`?