Installing and Using Portainer
Docker
07.05.2024
Reading time: 12 min
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Portainer is a container management tool that seamlessly works with both Docker and Kubernetes.
It is available in two versions:
-
free and open Community Edition;
-
paid Business Edition with additional features for corporate clients.
In this article, we will focus on installing Portainer on Ubuntu 22.04 with Docker and using the Community Edition. Although we will use Ubuntu as an example, most of the steps are similar for other operating systems, making this tutorial applicable to a variety of use cases.
Portainer is excellent for both beginners and professionals. Its intuitive graphical interface greatly simplifies management, making container technology accessible even to those new to the field. Experienced users will also find a rich selection of options for fine-tuning and personalization.
The article will focus on installing, overviewing the main functions and settings, connecting an external server as an environment, and providing a practical example of deploying WordPress on an external server using Portainer.
Prerequisites
-
A computer or a cloud server running a Linux-based OS such as Ubuntu, Debian etc.
In this article, we'll demonstrate installing Portainer on a local machine; however, if you plan to use it as a team, the application can also be installed on a cloud server, providing centralized management and accessibility to all team members.
Installing Portainer in Docker
Step 1: Install Docker and Docker Compose
Before installing Portainer, make sure Docker is installed on your system. If it is, you can skip this step. Otherwise, run the following commands to install:
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh ./get-docker.shAfter installation, check the versions by running the commands:
docker -v
docker compose versionThis will confirm successful installation and show the versions of installed programs.
Step 2: Create a working directory
Create a directory for the application in /opt and move to it:
cd /opt
sudo mkdir hostmanportainer
cd ./hostmanportainerStep 3: Create a configuration file
Now create a docker-compose.yml file in the hostmanportainer directory. This file will describe the startup configuration. Use nano or any other text editor to create the file:
sudo nano docker-compose.ymlPaste the following content into the file:
version: "3.3"
services:
hostmanportainer:
image: portainer/portainer-ce:latest
container_name: hostmanportainer
environment:
- TZ=Europe/London
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- /opt/hostmanportainer/portainer_data:/data
ports:
- "8000:8000"
- "9443:9443"
restart: always
Description of parameters:
-
version: "3.3": Indicates the version of Docker-compose you are using. Version 3.3 is suitable for most modern applications. -
services: This section describes the services to start. -
hostmanportainer: Service name. Used as an identifier. -
image: portainer/portainer-ce:latest: Specifies the image to be used. The latest version of Community Edition is used here. -
container_name: hostmanportainer: Assigns a name to the container to make it easier to identify. -
environment: Allows you to set environment variables. For example,TZ=Europe/Londonsets the time zone of the container. -
volumes: -
/var/run/docker.sock: /var/run/docker.sockallows Portainer to communicate with Docker on your host; -
/opt/hostmanportainer/portainer_data:/datacreates a persistent data store. -
ports: -
"8000:8000"and"9443:9443"open the corresponding ports to access the Portainer. 9443 is used for HTTPS connection. -
restart: always: Ensures that the container will automatically restart when necessary, for example after a server reboot.
Step 4: Launch
After creating the configuration file, run Portainer with Docker using the command:
docker compose up -dStep 5: Access the Interface
Portainer is now running and accessible at https://<ip_or_localhost>:9443. Open this address in your browser to access the web interface.
Step 6: Create an Administrator Account
When you first log in, you will be asked to create an administrator account. Please note that the password requires a minimum of 12 characters. After completing the registration process, you will have access to the settings and container management functionality in the interface.
General Settings
To access the settings, go to the Settings section. Here we will cover the key settings that are most important for the basic configuration. We recommend reading the official documentation for a deeper understanding of all available settings.
- Application settings. In this section, you can configure settings such as the frequency of creating state snapshots and sending anonymous application usage statistics.
- App Templates. Here you can specify the URL of a JSON file with templates for quickly deploying containers. You can also use pre-installed templates, making launching new applications easier.
- SSL certificate. This section allows you to upload your own SSL certificates for a secure connection. While this is not required for a local installation, attaching your own SSL certificate increases security when deploying Portainer on a remote server.
- Backup up Portainer. This section allows you to create a backup copy of the application settings and configuration. It is useful for ensuring data security and simplifying migration to other systems.
- Authentication. Here you can configure the user session duration and select the authentication method. The following methods are available in Community Edition: Internal (default), LDAP, and OAuth. However, it is worth noting that configuring OAuth in Community Edition has limitations, and popular services such as Microsoft OAuth, Google OAuth, Github OAuth are not supported, which requires manual configuration. When using Internal authentication, you can change the password requirements, such as reducing the minimum number of characters.
To change your password, go to the upper right corner of the screen, click on your account name and select My account. This will allow you to update your password and other personal settings.
After studying the basic settings, let's move on to other important sections available in the left menu of the interface.
- Users. This section is for managing users. It is especially useful for working with a team as it allows you to restrict access to resources. Here you can create and manage individual users. In addition, in the Teams section you can create teams with different users for more granular access control. It should be noted that more advanced role settings are only available in the Business Edition.
- Registries. In the Registries section, users can configure access to image repositories. The management interface facilitates integration with popular repositories such as DockerHub, AWS ECR, Quay.io, ProGet, Azure and GitLab, allowing you to efficiently manage container images directly through a graphical user interface.
- Environments. The key section of Portainer for connecting to and managing external servers or environments. You can manage a variety of environments here, including Docker, Docker Swarm, Kubernetes, and ACI. Nomad is also available in the Business Edition. This section allows Portainer Server to manage multiple environments, simplifying scaling and infrastructure management.
Adding a new environment
To demonstrate the process of adding a new environment, we will connect a server on Ubuntu 22.04 with Docker pre-installed. This can be either a new server or a server on which containers are already running.
- Start by clicking the Add environment button in the Environments section.
- Select Docker Standalone and use the setup wizard by clicking Start Wizard.
- During the setup process, select Agent and run the following command on the server that you plan to connect as an environment:
docker run -d\
-p 9001:9001\
--name portainer_agent\
--restart=always \
-v /var/run/docker.sock:/var/run/docker.sock \
-v /var/lib/docker/volumes:/var/lib/docker/volumes \
portainer/agent:2.19.4This command will launch the Portainer Agent, allowing Portainer Server to connect to the server and manage containers.
- After successfully installing and launching the agent on the server, return to the web interface and complete the connection process by specifying the name of the environment and its address in the format
server_ip:9001. - Click Connect to complete the connection. After successfully adding an environment, a pop-up notification Environment created will be displayed in the interface.
Environments Settings
When you go to the Home page, you will see two environments: local (the device where the application is running) and the previously added server. After selecting the previously added server, the menu on the left will update, adding management functions for the environment.
Environment Management
- Images. The Images section displays all available images in the system. Here you can delete images individually or en masse, as well as download new images using the Pull image option.
- Networks. The Networks page displays all available networks. Using an intuitive setup wizard accessible through Add Network, users can create new networks, expanding the connectivity between containers.
- Volumes. The Volumes section contains information about all volumes. This section allows you to view existing volumes, delete them, or create new ones using the Add volume setup wizard.
- Containers. The Containers section provides extensive container management capabilities. In this section, all existing containers are visible. You can delete, suspend, activate, or restart them. The Quick Actions menu provides additional functions, including viewing container information, statistics, and console access.
To create a new container, click on Add container. For example. let's create a container with Nginx. Specify the name, the nginx image and set up the network ports: click on publish a new network port and enter port 9090 for host, and port 80 for container.
Next, click on the Deploy the container button below and wait until the container is deployed.
Upon completion, you will be redirected to the Container list page. After deploying the container, going to http://server_ip:9090 will show running Nginx.
Advanced Features: App Templates and Stacks
The App Templates section is a collection of pre-configured templates for deploying common applications and services. These templates are designed to simplify the process of creating new containers by minimizing the need for manual configuration. Users can choose from a variety of available templates that range from basic web servers to complex multi-tier applications.
When using a template, it is enough to specify some basic parameters, such as the container name, network settings and, in some cases, specific settings such as passwords or environment variables. This makes the App Templates section particularly useful for quickly testing new ideas and utilities, as well as learning and experimenting with new technologies.
Stacks are an efficient way to manage groups of containers. They are defined through docker-compose files. This simplifies the management of complex applications and provides automation and consistency in deployment.
Use Case: Using Stacks for WordPress Deployment
A special feature of Stacks is choosing the configuration definition method: you can use the built-in editor to directly write or edit Docker Compose files, download a ready-made docker-compose.yml file, or even connect a git repository to update and deploy containers automatically.
Now let's put this technology into practice. Using WordPress deployment as an example, we'll show you how to use Stacks to create and manage multi-container applications. This example will help you understand how to simplify and automate your application deployment processes using Stacks.
- In the Stacks section, click Add stack to open the configurator.
- Using the Web editor, describe the application configuration in YAML format. For WordPress and MariaDB database, the configuration might look like this:
services:
db:
image: mariadb:10.6.4-focal
command: '--default-authentication-plugin=mysql_native_password'
volumes:
- db_data:/var/lib/mysql
restart: always
expose:
- 3306
- 33060
environment:
- MYSQL_ROOT_PASSWORD=hostmantest
- MYSQL_DATABASE=hostman_wp
- MYSQL_USER=hostman
- MYSQL_PASSWORD=password
wordpress:
image: wordpress:latest
ports:
- 80:80
restart: always
environment:
- WORDPRESS_DB_HOST=db
- WORDPRESS_DB_USER=hostman
- WORDPRESS_DB_PASSWORD=password
- WORDPRESS_DB_NAME=hostman_wp
volumes:
db_data:- Environment variables can be placed in a separate section. In Environment variables select Advanced mode and specify the variables:
MYSQL_ROOT_PASSWORD=hostmantest
MYSQL_DATABASE=hostman_wp
MYSQL_USER=hostman
MYSQL_PASSWORD=password
WORDPRESS_DB_HOST=db
WORDPRESS_DB_USER=hostman
WORDPRESS_DB_PASSWORD=password
WORDPRESS_DB_NAME=hostman_wp- Remove the environment section from the main YAML file to avoid duplication:
services:
db:
image: mariadb:10.6.4-focal
command: '--default-authentication-plugin=mysql_native_password'
volumes:
- db_data:/var/lib/mysql
restart: always
expose:
- 3306
- 33060
wordpress:
image: wordpress:latest
ports:
- 80:80
restart: always
volumes:
db_data:- Click Deploy the stack. A bit later, if the deployment is successful, you will be redirected to the Stacks list page, where our Wordpress instance will be displayed.
Test your WordPress functionality by going to http://server_ip:80. You should see the WordPress start page, confirming successful deployment.
Conclusion
In our review, we covered all the important aspects of working with Portainer, from its installation with Docker to the details of deploying applications through Stacks. We took a detailed look at the tool's various features and settings, including user management, image repository handling, and environment coordination. The WordPress deployment example clearly showed how Portainer simplifies working with complex systems, making the management process more efficient. The article provided a comprehensive understanding of Portainer as a solution to simplify and streamline application deployment processes.
Docker
07.05.2024
Reading time: 12 min
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Docker
Docker Exec: Access, Commands, and Use Cases
docker exec is a utility that allows you to connect to an already running Docker container and execute commands without restarting or stopping it. This is very convenient for technical analysis, configuration, and debugging applications. For example, you can check logs, modify configurations, or restart services.
And on a cloud server in Hostman, this command helps manage running applications in real time, without rebuilding containers or interfering with the image.
How to Use docker exec: Parameters and Examples
Before using it, make sure Docker is installed and the container is running. If you are just starting out, check out the installation guide for Docker on Ubuntu 22.04.
The basic syntax of docker exec is:
docker exec [options] <container> <command>
Where:
<container> is the name or ID of the target container;
<command> is the instruction to be executed inside it.
Main Parameters:
-i — enables input mode;
-t — attaches a pseudo-terminal, useful for running bash;
-d — runs the task in the background;
-u — allows running the command as a specified user;
-e — sets environment variables;
-w — sets the working directory in which the command will be executed.
Example of launching bash inside a container:
docker exec -it my_container /bin/bash
This way, you can access the container’s environment and run commands directly without stopping it.
Usage Examples
List files inside the container:
ls /app
Run commands with root access:
docker exec -u root my_container whoami
Pass environment variables:
docker exec -e DEBUG=true my_container env
Set working directory:
docker exec -w /var/www my_container ls
Run background tasks:
docker exec -d my_container touch /tmp/testfile
Check Nginx configuration inside a container before restarting it:
docker exec -it nginx_container nginx -t
Advanced Use Cases
Let’s consider some typical but slightly more complex scenarios that may be useful in daily work: running as another user, passing multiple environment variables, specifying a working directory, etc.
Run as web user:
docker exec -u www-data my_container ls -la /var/www
Set multiple environment variables at once:
docker exec -e DEBUG=true -e STAGE=dev my_container env
Set working directory with admin rights:
docker exec -u root -w /opt/app my_container ls
Example with Laravel in Hostman
If you deploy a Laravel application in a container on a Hostman server, docker exec will be very handy. Suppose you have a container with Laravel and a database in a separate service.
To connect to the server:
ssh root@your-server-ip
After connecting, you can run Artisan commands—Laravel’s built-in CLI—inside the container.
Clear application cache:
docker exec -it laravel_app php artisan cache:clear
Run migrations:
docker exec -it laravel_app php artisan migrate
Check queue status:
docker exec -it laravel_app php artisan queue:listen
Set permissions:
docker exec -u www-data -it laravel_app php artisan config:cache
Make a backup of a database deployed in a separate container:
docker exec -it mariadb_container mysqldump -u root -p laravel_db > backup.sql
Before running the last command, make sure that a volume for /backup is mounted, or use SCP to transfer the file to your local machine.
This approach does not require changing the image or direct container access, which makes administration safe and flexible.
Extended Capabilities of docker exec
In this section, we will look at less common but more flexible uses of the docker exec command: for example, running psql in a PostgreSQL container, executing Node.js scripts, or connecting to stopped containers. These cases show how flexible the command can be if something non-standard is required.
The command is not limited to basic tasks: in addition to launching shell or bash, you can work with environments, interact with databases, run Node.js scripts, and connect to any running container.
Connect to PostgreSQL CLI:
docker exec -it postgres_container psql -U postgres -d my_db
Run a Node.js script (if you have script.js):
docker exec -it node_app node script.js
Run a stopped container:
docker start my_container
docker exec -it my_container bash
Manage users explicitly with -u:
docker exec -u www-data my_container ls -la /var/www
Quickly remove temporary files:
docker exec -it my_container rm -rf /tmp/cache/*
This approach is convenient in cron jobs or when manually cleaning temporary directories.
When Not to Use the Command
Despite its convenience, docker exec is a manual tool for interacting with containers. In production environments, its use can be risky.
Why not use docker exec in production:
Changes are not saved in Dockerfile. This can break reproducibility and infrastructure integrity.
No command logging, so it’s difficult to track actions.
Possible desynchronization with CI/CD pipeline.
Instead, it is recommended to use:
Dockerfile and docker-compose.yml for reproducible builds;
CI/CD for automating tasks via GitHub Actions or GitLab CI;
Monitoring for log processes with Prometheus, Grafana, and Loki.
Troubleshooting Common Errors
No such container
Cause: container not found or stopped
Solution:
docker ps
The command shows a list of running containers. If your container is not listed, it’s not running or hasn’t been created.
exec failed: container not running
Cause: attempt to run a command in a stopped container
Solution:
docker start <container_name>
After starting the container, you can use docker exec again.
permission denied
Cause: insufficient user permissions
Solution:
docker exec -u root <container> <command>
The -u root flag runs the command as root, providing extended access inside the container. This is especially useful when working with system files or configurations.
Difference Between docker exec and docker attach
In addition to docker exec, there is another way to interact with a container—the docker attach command. It connects you directly to the main process running inside the container, as if you launched it in the terminal.
This is convenient if you need to monitor logs or enter data directly, but there are risks: any accidental key press (for example, Ctrl+C) can stop the container. That’s why it’s important to understand the differences.
Also, docker attach requires TTY (a terminal emulator) for correct work with interactive apps like bash or sh.
Parameter
docker exec
docker attach
Requires TTY
Optional
Yes
Multiple connections
Yes
No
Interferes with main process
No
Yes
Usable for debugging
Yes
Partially (may harm app)
Use docker exec for auxiliary tasks—it provides flexibility and reduces risks.
Conclusion
The docker exec command is an effective tool for managing containers without interfering with their lifecycle. It allows you to run commands as different users, pass variables, check logs, and perform administrative tasks.
When working in cloud services such as Hostman, this is especially useful: you can perform targeted actions without rebuilding the image and without risking the main process.
It is important to remember: docker exec is a manual tool and does not replace automated DevOps approaches. For system-level changes, it is better to use Dockerfile and CI/CD, keeping your infrastructure reproducible and secure.
05 September 2025 · 6 min to read
Docker
How to Install Docker on Ubuntu 22.04
Docker is a free, open-source tool for application containerization. Containers are isolated environments similar to virtual machines (VMs), but they are more lightweight and portable across platforms, requiring fewer system resources. Docker uses OS-level virtualization, leveraging features built into the Linux kernel.
Apps order after installing Docker on Ubuntu
Although it applies to other Ubuntu versions as well, this tutorial explains how to install Docker on Ubuntu 22.04. We'll also download Docker Compose, which is a necessary tool for effectively managing several containers.
For this guide, we will use a Hostman cloud server.
System Requirements
According to Docker's documentation, the following 64-bit Ubuntu versions are supported:
Ubuntu Oracular 24.10
Ubuntu Noble 24.04 (LTS)
Ubuntu Jammy 22.04 (LTS)
Ubuntu Focal 20.04 (LTS)
Docker works on most popular architectures. The resource requirements for your device will depend on your intended use and how comfortably you want to work with Docker. The scale of applications you plan to deploy in containers will largely dictate the system needs. Some sources recommend a minimum of 2 GB of RAM.
Additionally, a stable internet connection is required.
Installing Docker on Ubuntu 22.04
Installing Docker on Ubuntu 22.04 involves executing a series of terminal commands. Below is a step-by-step guide with explanations. The steps are also applicable to server versions of Ubuntu.
1. Update Package Indexes
The default repository may not always contain the latest software releases. Therefore, we will download Docker from its official repository to ensure the latest version. First, update the package indexes:
sudo apt update
2. Install Additional Packages
To install Docker, you’ll need to download four additional packages:
curl: Required for interacting with web resources.
software-properties-common: Enables software management via scripts.
ca-certificates: Contains information about certification authorities.
apt-transport-https: Necessary for data transfer over the HTTPS protocol.
Download these packages with the following command:
sudo apt install curl software-properties-common ca-certificates apt-transport-https -y
The -y flag automatically answers "Yes" to all terminal prompts.
3. Import the GPG Key
Software signatures must be verified using the GPG key. Docker's repository must be added to the local list. Use the command to import the GPG key:
wget -O- https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor | sudo tee /etc/apt/keyrings/docker.gpg > /dev/null
During the import process, the terminal may display a warning before confirming the successful execution of the command.
4. Add Docker Repository
Add the repository for your version of Ubuntu, named "Jammy." For other versions, use their respective code names listed in the "System Requirements" section. Run the following command:
echo "deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu jammy stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
During execution, the terminal will prompt you to confirm the operation. Press Enter.
5. Update Package Indexes Again
After making these changes, update the package indexes once more using the familiar command:
sudo apt update
6. Verify the Repository
Ensure that the installation will proceed from the correct repository by running the following command:
apt-cache policy docker-ce
Output example:
Depending on the most recent Docker releases, the result could change. Verifying that the installation will be carried out from Docker's official repository is crucial.
7. Installing Docker
After configuring the repositories, proceed with the Docker installation:
sudo apt install docker-ce -y
The installation process will begin immediately. To confirm a successful installation, check Docker's status in the system:
sudo systemctl status docker
Output example:
The output should indicate that the Docker service is active and running.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
Installing Docker Compose
Docker Compose is a Docker tool designed for managing multiple containers. It is commonly used in projects where many containers must work together as a unified system. Managing this process manually can be challenging. Instead, you describe the entire configuration in a single YAML file containing the settings and configurations for all containers and their applications.
There are several ways to install Docker Compose. If you need the latest version, make sure to use manual installation and installation via the Git version control system.
Installation via apt-get
If having the latest version is not critical for you, Docker Compose can be installed directly from the Ubuntu repository. Run the following command:
sudo apt-get install docker-compose
Installing via Git
First, install Git:
sudo apt-get install git
Verify the installation by checking the Git version:
git --version
The output should show the Git version.
Next, clone the Docker Compose repository. Navigate to the Docker Compose GitHub page and copy the repository URL.
Run the following command to clone the repository:
git clone https://github.com/docker/compose.git
The cloning process will begin, and the repository will be downloaded from GitHub.
Manual Installation
Go to the Docker Compose GitHub repository and locate the latest release version under the Latest tag.
At the time of writing, the Latest version of Docker Compose is v2.31.0. Let's download it:
sudo curl -L "https://github.com/docker/compose/releases/download/v2.31.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
In this command, the parameters $(uname -s) and $(uname -m) automatically account for the system characteristics and architecture. After the download finishes, change the file's permissions:
sudo chmod +x /usr/local/bin/docker-compose
Right order of your infrastructure after installation of Docker on Ubuntu
Conclusion
In this guide, we covered the installation of Docker on Ubuntu 22.04, along with several ways to install Docker Compose. You can order a cloud server at Hostman for your experiments and practice.
22 August 2025 · 5 min to read
Docker
Running Selenium with Chrome in Docker
Sometimes, it’s useful to work with Selenium in Python within a Docker container. This raises questions about the benefits of using such tools, version compatibility between ChromeDriver and Chromium, and the nuances of their implementation. In this article, we’ll cover key considerations and provide solutions to common issues.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
Why Run Selenium in Docker?
Running Selenium in a container offers several advantages:
Portability: Easily transfer the environment between different machines, avoiding version conflicts and OS-specific dependencies.
Isolation: The Selenium container can be quickly replaced or updated without affecting other components on the server.
CI/CD Compatibility: Dockerized Selenium fits well into CI/CD pipelines — you can spin up a clean test environment from scratch each time your system needs testing.
Preparing an Ubuntu Server for Selenium with Docker
First, make sure Docker and Docker Compose are installed on the server:
docker --version && docker compose version
In some Docker Compose versions, the command is docker-compose instead of docker compose.
If the tools are installed, you’ll see output confirming their versions. If not, follow this guide.
Selenium in Docker Example
When deploying Selenium in Docker containers, consider the host architecture, functional requirements, and performance. Official selenium/standalone-* images are designed for AMD64 (x86_64) CPUs, while seleniarm/standalone-* images are adapted for ARM architectures (e.g., Apple silicon or ARM64 server CPUs).
First, create a docker-compose.yml file in your project root. It will contain two services:
version: "3"
services:
app:
build: .
restart: always
volumes:
- .:/app
depends_on:
- selenium
platform: linux/amd64
selenium:
image: selenium/standalone-chromium:latest # For AMD64
# image: seleniarm/standalone-chromium:latest # For ARM64
container_name: selenium-container
restart: unless-stopped
shm_size: 2g
ports:
- "4444:4444" # Selenium WebDriver API
- "7900:7900" # VNC Viewer
environment:
- SE_NODE_MAX_SESSIONS=1
- SE_NODE_OVERRIDE_MAX_SESSIONS=true
- SE_NODE_SESSION_TIMEOUT=300
- SE_NODE_GRID_URL=http://localhost:4444
- SE_NODE_DETECT_DRIVERS=false
You must choose the correct image for your system architecture by uncommenting the appropriate line.
The app service will run your main Python code. Let’s define a standard Dockerfile for this service:
# Use a minimal Python image
FROM python:3.11-slim
# Set working directory
WORKDIR /app
# Install Python dependencies
COPY requirements.txt /app/
RUN pip install --no-cache-dir -r requirements.txt
# Copy project files
COPY . /app/
# Set environment variables (Chromium is in a separate container)
ENV SELENIUM_REMOTE_URL="http://selenium:4444/wd/hub"
# Run Python script
CMD ["python", "main.py"]
This Dockerfile uses a base Python image and automatically installs the necessary dependencies.
Now let’s add the driver initialization script to main.py:
import time # Used to create a delay for checking browser functionality
import os
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options
# WebDriver settings
chrome_options = Options()
chrome_options.add_argument("--no-sandbox")
chrome_options.add_argument("--disable-dev-shm-usage")
chrome_options.add_argument("--disable-gpu")
chrome_options.add_argument("--disable-webrtc")
chrome_options.add_argument("--hide-scrollbars")
chrome_options.add_argument("--disable-notifications")
chrome_options.add_argument("--start-maximized")
SELENIUM_REMOTE_URL = os.getenv("SELENIUM_REMOTE_URL", "http://selenium:4444/wd/hub")
driver = webdriver.Remote(
command_executor=SELENIUM_REMOTE_URL,
options=chrome_options
)
# Open a test page
driver.get("https://www.timeweb.cloud")
time.sleep(9999)
# Shut down WebDriver
driver.quit()
In the requirements.txt file, list standard dependencies, including Selenium:
attrs==25.1.0
certifi==2025.1.31
h11==0.14.0
idna==3.10
outcome==1.3.0.post0
PySocks==1.7.1
selenium==4.28.1
sniffio==1.3.1
sortedcontainers==2.4.0
trio==0.28.0
trio-websocket==0.11.1
typing_extensions==4.12.2
urllib3==2.3.0
websocket-client==1.8.0
wsproto==1.2.0
Now you can launch the containers:
docker compose up -d
Expected output: Docker will build and launch the containers.
To verify everything is running correctly:
docker compose ps
You should see two running containers which means everything was loaded successfully. You can now integrate a script in main.py to interact with any site.
Debugging Selenium in Docker with VNC
In official Selenium Docker images (like seleniarm/standalone-chromium, selenium/standalone-chrome, etc.), direct access to the Chrome DevTools Protocol is usually overridden by Selenium Grid. It generates a new port for each session and proxies it via WebSocket.
Arguments like --remote-debugging-port=9229 are ignored or overwritten by Selenium, making direct browser port access impossible from outside the container.
Instead, these Docker images offer built-in VNC (Virtual Network Computing), similar to TeamViewer or AnyDesk, but working differently.
VNC requires headless mode to be disabled, since it transmits the actual screen content — and if the screen is blank, there will be nothing to see.
You can connect to the VNC web interface at:
http://<server_ip>:7900
When connecting, you'll be asked for a password. To generate one, connect to the selenium-container via terminal:
docker exec -it selenium-container bash
Then enter:
x11vnc -storepasswd
You’ll be prompted to enter and confirm a password interactively.
Enter the created password into the VNC web interface, and you’ll gain access to the browser controlled by Selenium inside Docker.
From there, you can open DevTools to inspect DOM elements or debug network requests.
Conclusion
Running Selenium in Docker containers simplifies environment portability and reduces the risk of version conflicts between tools. It also allows visual debugging of tests via VNC, if needed. Just make sure to choose the correct image for your system architecture and disable headless mode when a graphical interface is required. This provides a more flexible and convenient infrastructure for testing and accelerates Selenium integration into CI/CD pipelines.
19 June 2025 · 6 min to read
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