fabulargirl · fabulargirl · Jul 12, 2025 · Jul 5, 2025
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+# Task 0: Image Exporting
+
+1. Export Image
+   - Install image.
+
+    Command: `docker pull ubuntu:latest `
+
+    - Image information: 
+
+    Command: `docker images`
+
+    Output: 
+    ```commandline
+    REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
+    ubuntu       latest    70ed52c84b4e   2 weeks ago   101MB
+   ```
+
+tar size = 103,1 МБ
+
+Original size = 101MB
+
+![img.png](Images/img_lab6.png)
+
+The original image is the size of the image in Docker storage.
+The size in docker image ls shows the total amount of unique data in the image excluding common layers.
+
+tar size is the size of the image packed in a .tar archive.
+Includes all layers + metadata even if the layers are compressed, they may take up more space due to the archive structure.
+
+# Task 1: Core Container Operations
+
+1. **List Containers**
+
+    Command: `docker ps -a`
+
+    Output: 
+
+    `CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES`
+
+2. **Pull Ubuntu Image**
+
+    Command: `docker pull ubuntu:latest`
+
+    Original size = 101MB
+
+3. **Run Interactive Container**
+
+Command: `docker run -it --name ubuntu_container ubuntu:latest`
+
+Output:
+```commandline
+root@a847291fdb82:/# exit
+exit
+```
+
+4. **Remove Image**
+
+Command: `docker rmi ubuntu:latest`
+
+Output:
+```commandline
+Error response from daemon: conflict: unable to remove repository reference "ubuntu:latest" (must force) - container a847291fdb82 is using its referenced image 70ed52c84b4e
+```
+
+The command is fails because ubuntu:latest image is used by the container. Docker does not allow you to delete an image if containers depend on it.
+
+# Task 2: Image Customization
+
+1. **Deploy Nginx**
+
+    Command: `docker run -d -p 80:80 --name nginx_container nginx`
+
+    Verification with `curl localhost`:
+
+    ```html
+    <!DOCTYPE html>
+    <html>
+    <head>
+    <title>Welcome to nginx!</title>
+    <style>
+    html { color-scheme: light dark; }
+    body { width: 35em; margin: 0 auto;
+    font-family: Tahoma, Verdana, Arial, sans-serif; }
+    </style>
+    </head>
+    <body>
+    <h1>Welcome to nginx!</h1>
+    <p>If you see this page, the nginx web server is successfully installed and
+    working. Further configuration is required.</p>
+
+    <p>For online documentation and support please refer to
+    <a href="http://nginx.org/">nginx.org</a>.<br/>
+    Commercial support is available at
+    <a href="http://nginx.com/">nginx.com</a>.</p>
+
+    <p><em>Thank you for using nginx.</em></p>
+    </body>
+    </html>
+    ```
+
+2. **Customize Website**
+
+   - Create an HTML file with the specified content:
+
+    ![img.png](Images/img_lab6(1).png)
+
+   - Copy the HTML file to the container:
+
+    Command: `docker cp index.html nginx_container:/usr/share/nginx/html/`
+
+    Output: `Successfully copied 2.05kB to nginx_container:/usr/share/nginx/html/`
+
+
+3. **Create Custom Image**
+
+    Command: `docker commit nginx_container my_website:latest`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(2).png)
+
+4. **Remove Original Container**
+
+    Command: `docker rm -f nginx_container`
+
+    Result:
+
+    ![img.png](Images/img_lab6(3).png)
+
+5. **Create New Container**
+
+    Command: `docker run -d -p 80:80 --name my_website_container my_website:latest`
+
+    Result:
+
+    ![img.png](Images/img_lab6(4).png)
+
+6. **Test Web Server:**
+
+    Command: `curl http://127.0.0.1:80`
+
+    Result:
+
+    ![img.png](Images/img_lab6(5).png)
+
+7. **Analyze Image Changes:**
+
+    Command: `docker diff my_website_container`
+
+    Rsult: 
+    ```commandline
+    C /etc
+    C /etc/nginx
+    C /etc/nginx/conf.d
+    C /etc/nginx/conf.d/default.conf
+    C /run
+    C /run/nginx.pid
+    ```
+
+    This means that the following files and directories have changed in the container:
+
+    If the container runs Nginx, when it starts:
+
+    1. Generates settings in /etc/nginx/conf.d/default.conf.
+
+    2. Creates a PID file (/run/nginx.pid) to control the process.
+
+    3. These changes are normal for a running container with a web server./nginx.pid - Nginx Process ID (PID) file changed when the web server was restarted.
+
+# Task 3: Container Networking
+
+1. **Create Network:**
+
+    Create a bridge network named `lab_network`
+
+    Command: `docker network create lab_network`
+
+    Result:
+
+    ![img.png](Images/img_lab6(6).png)
+
+2. **Run Connected Containers:**
+
+    Start two Alpine containers attached to the network:
+
+    Commands:
+
+    ```commandline
+    docker run -dit --network lab_network --name container1 alpine ash
+    docker run -dit --network lab_network --name container2 alpine ash
+    ```
+    Result: 
+
+    ![img.png](Images/img_lab6(7).png)
+
+3. **Test Connectivity:**
+
+    From container1, ping container2 by name
+
+    Command: `docker exec container1 ping -c 3 container2`
+
+    Result: 
+
+    ![img_1.png](Images/img_lab6(8).png)
+
+4. **Explain how Docker's internal DNS resolution works**
+
+    Docker's built-in DNS allows containers to communicate with each other by name while on the same network. But DNS only works within the user's network.
+
+# Task 4: Volume Persistence
+
+1. **Create Volume:**
+
+    Command: `docker volume create app_data`
+
+2. **Run Container with Volume:**
+
+    Command: `docker run -d -v app_data:/usr/share/nginx/html --name web nginx`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(9).png)
+
+3. **Modify Content:**
+
+    Command: `docker cp index.html web:/usr/share/nginx/html/`
+
+    Result:
+
+    ![img.png](Images/img_lab6(10).png)
+
+4. **Verify Persistence:**
+
+   - Stop and remove container:
+
+       Command: `docker stop web && docker rm web`
+   - Create new container with same volume:
+
+       Command: `docker run -d -v app_data:/usr/share/nginx/html --name web_new nginx`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(11).png)
+
+# Task 5: Container Inspection
+
+1. **Run Redis Container:**
+
+    Command: `docker run -d --name redis_container redis`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(12).png)
+
+2. **Inspect Processes:**
+
+    Find Redis server process:
+
+    Command: `docker exec redis_container ps aux`
+
+3. **Network Inspection:**
+
+    Get container IP address:
+
+    Command: `docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' redis_container`
+
+    Result:
+
+    ![img.png](Images/img_lab6(13).png)
+
+4. **Compare `docker exec` vs `docker attach`**
+
+    `docker exec`:
+
+    1. Runs a new command inside an already-running container.
+    2. Creates a new process alongside the container’s main process.
+
+    Key Use Cases:
+    1. Run one-off commands 
+    2. Debugging
+    3. Modify files or install tools without interrupting the main process
+
+    `docker attach`:
+
+    1. Attaches your terminal to the container’s primary process.
+    2. Connects to the exact same input/output streams as the original process.
+
+    Key Use Cases:
+
+    1. Interact with foreground processes
+    2. View real-time output of the main process
+
+# Task 6: Cleanup Operations
+
+1. **Verify Cleanup:**
+
+    Check disk usage:
+
+    Command: `docker system df`
+
+    Output: 
+    ![img.png](Images/img_lab6(14).png)
+
+2. **Create Test Objects:**
+
+   - Create 3 stopped containers:
+
+       Command: `for i in {1..3}; do docker run --name temp$i alpine echo "hello"; done`
+
+       Result:
+
+       ![img.png](Images/img_lab6(15).png)
+
+   - Create 2 dangling images:
+
+       Command: `docker build -t temp-Images . && docker rmi temp-images`
+
+       Result:
+
+       ![img.png](Images/img_Lab6(16).png)
+
+3. **Remove Stopped Containers:**
+
+    Command: `docker container prune -f`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(17).png)
+
+4. **Remove Unused Images:**
+
+    Command: `docker Images prune -a -f`
+
+5. **Verify Cleanup:**
+
+    Command: `docker system df`
+
+    Result: 
+
+    ![img.png](Images/img_lab6(18).png)