What’s wrong with the Container?

I wanted to provision a Japanese version of my website but one of the containers kept on restarting. I couldn’t figure out what’s wrong with it for a while.

I finally figured out how to view the log of the container.

docker logs --tail 50 --follow --timestamps [container ID]

Here is the log output.

2022-03-13T05:46:44.573226016Z /docker-entrypoint.sh: Configuration complete; ready for start up
2022-03-13T05:46:44.579540345Z 2022/03/13 05:46:44 [emerg] 1#1: cannot load certificate "/home/opc/wordpress/nginx/conf.d/ssl/cert1.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/home/opc/wordpress/nginx/conf.d/ssl/cert1.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)
2022-03-13T05:46:44.579598505Z nginx: [emerg] cannot load certificate "/home/opc/wordpress/nginx/conf.d/ssl/cert1.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/home/opc/wordpress/nginx/conf.d/ssl/cert1.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)

Of course, I made a mistake in specifying the path of the certificate files. When I corrected it, the site came up correctly.

Ansible WordPress Repo

I guess I finished my personal project of provisioning WordPress site with Ansible. I was able to run it and get a WordPress site to show up in just about 10 mins. I’m sure there are some loose end I could tighten but it generally works. Here is the GitHub repo I worked on.

ansible-wordpress repo on GitHub

Setting up a free OCI account (ARM64 Oracle Linux 8 is always free eligible) and getting a domain name through dnsimple.com are two things you may need to do but if you pay like $60 for dnsimple.com (DNS service) annually, you get to have your own full blown WordPress site with your own domain name.

One thing to be careful about this approach is that you have the full control over the site, meaning if there is any issue, you are on your own to analyze and resolve the issue. You have to update your SSL cert yourself as well. If you are not so good with Linux or have no willingness to dig into it, it wouldn’t be for you.

If you are a CS student wanting your own site or you are learning how websites work, you may want to dig into it. After all, just $60 per year to have your own WordPress site with your own domain name is really reasonable.

WordPress Site with Ansible

This site is served on Oracle Linux 7 (ARM64) and Docker containers of WordPress, NGINX, Maria DB and phpMyAdmin. Since the time when I figured out how to have WordPress on Docker on a Linux host, I have configured this site manually multiple times. It’s not crazy hard but it’s still some work.

I thought about automating it but I just didn’t have a chance. Now that I’ve been learning Ansible, I feel I can make that happen. Just execute a command and it will automatically configure a WordPress site wherever your host is.

I’m starting a repo on GitHub. I will be pushing what I come up with.

How to Install Docker Compose 2 on Intel x86_64 Processor

I’m guessing most of the people out there still use Intel x86_64 processor. I am writing a blog article on how to install Docker Compose 2 on it.

  1. Create a directory.
    mkdir -p ~/.docker/cli-plugins/
  2. Download Docker Compose 2 binary for x86_64.
    curl -SL https://github.com/docker/compose/releases/download/v2.2.3/docker-compose-linux-x86_64 -o ~/.docker/cli-plugins/docker-compose
  3. Give the binary file execute permission.
    chmod +x ~/.docker/cli-plugins/docker-compose
  4. Check if the binary has been installed successfully.
    docker compose version
  5. You should an output like the image below.

How to Install Docker Engine with Ansible on Oracle Linux 7

I am wanting to make sure Docker engine is present on my Jenkins host. To prove that Docker is not installed yet, here is the result of sudo systemctl status docker on the Jenkins host.

Unit docker.service could not be found.

Here is the Ansible playbook I came up with. The target host is an Oracle Linux 7 on ARM64 processor.

- name: Install docker
  gather_facts: No
  hosts: jenkins

    - name: Install Docker
        name: docker-engine
        state: installed
      become: yes
    - name: Enable/Start Docker
        name: docker
        enabled: yes
        state: started
      become: yes

    - name: Add user vagrant to docker group
        name: vagrant
        groups: docker
        append: yes
      become: yes

Here is the result when I execute it.

ansible-playbook playbooks/docker-ce.yaml
PLAY [Install docker] ****************************************************************************************************************************

TASK [Install Docker] ****************************************************************************************************************************
changed: [jenkins.hayato-iriumi.net]

TASK [Enable/Start Docker] ***********************************************************************************************************************
changed: [jenkins.hayato-iriumi.net]

TASK [Add user vagrant to docker group] **********************************************************************************************************
ok: [jenkins.hayato-iriumi.net]

PLAY RECAP ***************************************************************************************************************************************
jenkins.hayato-iriumi.net  : ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

When I ssh into the Jenkins host and check if Docker daemon is running here is the output.

[opc@jenkins ~]$ sudo systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2022-01-03 04:55:11 GMT; 1min 37s ago
     Docs: https://docs.docker.com
 Main PID: 18476 (dockerd)
    Tasks: 8
   Memory: 37.5M
   CGroup: /system.slice/docker.service
           └─18476 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Jan 03 04:55:10 jenkins dockerd[18476]: time="2022-01-03T04:55:10.694835968Z" level=warning msg="Your kernel does not support cgroup blkio weight"
Jan 03 04:55:10 jenkins dockerd[18476]: time="2022-01-03T04:55:10.695237969Z" level=warning msg="Your kernel does not support cgroup bl..._device"
Jan 03 04:55:10 jenkins dockerd[18476]: time="2022-01-03T04:55:10.695923611Z" level=info msg="Loading containers: start."
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.014165992Z" level=info msg="Default bridge (docker0) is assigned with...address"
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.130298822Z" level=info msg="Loading containers: done."
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.147750103Z" level=warning msg="Not using native diff for overlay2, th...overlay2
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.148281344Z" level=info msg="Docker daemon" commit=9bb540d graphdriver...03.11-ol
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.148597025Z" level=info msg="Daemon has completed initialization"
Jan 03 04:55:11 jenkins systemd[1]: Started Docker Application Container Engine.
Jan 03 04:55:11 jenkins dockerd[18476]: time="2022-01-03T04:55:11.208274084Z" level=info msg="API listen on /var/run/docker.sock"
Hint: Some lines were ellipsized, use -l to show in full.

Migrated to ARM64 Oracle Linux 7

I have migrated my site to Oracle Linux 7 on ARM64 just because I was curious how it would work on ARM64 or if it would work on ARM64 at all.

As of this writing, I’ve got this WordPress site on Docker to work on Oracle Linux 7 on ARM64 processor. It was some struggle but I feel it’s snappier.

Here is the Docker Compose file that works for this site. As you can see, I commented out the mysql image and using Maria DB for ARM64 instead. Maria DB is a fork for MySQL, so it’s sufficient enough for my personal blog site.

version: "3.9"
    image: arm64v8/mariadb # mysql/mysql-server:8.0.20-aarch64
      - ./mysql:/var/lib/mysql
    restart: always
    command: mysqld --default-authentication-plugin=mysql_native_password
      MYSQL_ROOT_PASSWORD: YourPassword
      MYSQL_DATABASE: hayato_iriumi_db
      MYSQL_USER: blog_admin
      MYSQL_PASSWORD: AnotherPassword
      - db
    image: arm64v8/phpmyadmin
    restart: always
      - '8080:80'
      PMA_HOST: db
      MYSQL_ROOT_PASSWORD: YourPassword
    image: arm64v8/wordpress
    container_name: wordpress
      - db
        # ports:
        # - "8000:80"
    restart: always
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_USER: blog_admin
      WORDPRESS_DB_PASSWORD: AnotherPassword
      WORDPRESS_DB_NAME: hayato_iriumi_db
      WORDPRESS_DEBUG: 'true'
      - ./html:/var/www/html
      - ./wp-content:/var/www/html/wp-content
    image: arm64v8/nginx
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
      - ./nginx/conf.d:/etc/nginx/conf.d
      - "80:80"
      - "443:443"
    restart: always
  db_data: {}
  wordpress: {}

Docker Compose 2 works well on ARM64 as well. It is definitely faster than Docker Compose 1. By just changing the platform, I feel I upgraded my blog site for a better performance.

How to Install Docker Compose 2 on ARM Processor Linux Host (OL7)

I have provisioned Oracle Linux 7 on ARM processor on OCI. In an attempt to get my blog site to work on the host, I have installed Docker engine and now I want to install Docker Compose 2. Here are the steps.

  1. Create a directory.
    mkdir -p ~/.docker/cli-plugins/
  2. Download the Docker Compose 2 binary for ARM64.
    curl -SL https://github.com/docker/compose/releases/download/v2.2.2/docker-compose-linux-armv7 -o ~/.docker/cli-plugins/docker-compose
  3. Give the binary file execute permission.
    chmod +x ~/.docker/cli-plugins/docker-compose
  4. Check if the binary has been installed successfully.
    docker compose version

Not Working on ARM Host

I spined up an ARM host on OCI and installed Docker Compose 2 and then downloaded my docker-compose.yaml file to start my blog engine on it, but I got the following error.

This means no image is available for ARM64. I don’t think there is anything I can do at the moment (unless I make the effort and create images myself), so I am giving it up for now. Oh well…

Edit: I did some research to see if those Docker images are available and they are. I will give it another try.

How to Generate Free SSL by Let’s Encrypt

I attempted to use Certbot by Let’s Encrypt for free SSL certificate for my subdomain using a Docker container but it was never successful, so I left it alone for a while. The DNS service that I use provides SSL certs but it charges me extra for subdomain. There are other services such as SSL for Free but they either limit the number of certificates or they charge for subdomains or they want me to pay like $10 per month for wildcard certificate. That’s pretty steep considering the host is being used only privately. The alternative is to create your own private CA authority and issue SSL cert and have the root CA cert on the machines that you use the hosts.

But this morning, I figured out a way to generate the free SSL cert for my subdomain using Certbot. I will write about what worked for me.

I followed this instruction to install snapd on Ubuntu.

First, remove certbot if installed by apt.

sudo apt-get remove certbot

Install Certbot.

sudo snap install --classic certbot

Prepare the Certbot command.

sudo ln -s /snap/bin/certbot /usr/bin/certbot

Now prepare your NGINX server to accept HTTP traffic for acme challenge.

Edit nginx.conf to accept HTTP (port 80).

   server {
      location / {
          root   /var/www/html;
          index  index.html index.htm;
      listen       80 default_server;
      listen       [::]:80 default_server;
      server_name  _;

If you have the HTTP redirect to HTTPS, uncomment the line.

# return 301 https://jenkins.hayato-iriumi.net$request_uri;

Now back to Certbot, execute the following command to start to issue your ssl cert.

sudo certbot certonly -a manual --rsa-key-size 4096 --email hiriumi@gmail.com -d jenkins.hayato-iriumi.net

You will see an output like the following.

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator manual, Installer None
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for jenkins.hayato-iriumi.net

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.

Are you OK with your IP being logged?
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(Y)es/(N)o: Y

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create a file containing just this data:


And make it available on your web server at this URL:


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Press Enter to Continue

Now you should create the file with the data specified in the output. Once you have that hit Enter to get the cert generated.

Lastly, when the cert generation is successful, you will see the output like the following.

Now switch to the root user by executing…

sudo -i

The cert files are at /etc/letsencrypt/archive/jenkins.hayato-iriumi.net

Copy cert1.pem and privkey1.pem to the directory where you would like to store your SSL files. In my ssl.conf file, I have specified the cert files like the following.

server {
    server_name jenkins.hayato-iriumi.net;
    listen 443 ssl;
    ssl_certificate /etc/nginx/conf.d/ssl/cert1.pem;
    ssl_certificate_key /etc/nginx/conf.d/ssl/privkey1.pem;
    client_max_body_size 3000m;

Now unc0mment the line in ssl.conf to redirect HTTP to HTTPS traffic. Once you restart your NGINX, NGINX starts to service the traffic in SSL.

I’m sure there are ways to automate this and I am thinking of exploring the way to do it but it works well for now.