Jenkins＆Ansible在线测试

Analyze the following Ansible playbook, which is designed to set up and verify a web server. Determine the correct order of task execution, including the handler invocation:

In what order will the tasks and handlers be executed?

A: Install web server, Start web server, Verify web server, Notify failure, Restart web server (if notified)
B: Install web server, Start web server, Restart web server (if notified), Verify web server, Notify failure (if failed)
C: Install web server, Restart web server (if notified), Start web server, Verify web server, Notify failure (if failed)
D: Install web server, Start web server, Verify web server, Notify failure (if failed), Restart web server (if notified)
E: Install web server, Verify web server, Start web server, Restart web server (if notified), Notify failure (if failed)
F: Install web server, Start web server, Verify web server (if previous task failed), Notify failure, Restart web server (if notified)

You are a senior Ansible engineer tasked with writing a playbook to configure a set of web servers. The playbook should iterate over a list of packages and install them. However, if a package installation fails, the playbook should record the failed package name and continue with the next package without failing the entire playbook. The playbook also needs to generate a report at the end, listing all successfully installed packages and any that failed to install. Below is the pseudo code for the main task:

Select the correct way to complete this playbook:

A: Add a block with a rescue section after the loop to capture failed packages.
B: Use failed_when in the loop to prevent the task from failing and update the lists accordingly.
C: Use a when condition inside the loop to check package_result.failed and update the lists.
D: Add a handler triggered on package installation failure to update the failed_packages list.
E: Use a Jinja2 template in a separate task to generate the report after the loop.
F: Implement a custom Ansible module for package installation and failure handling.

Consider an Ansible playbook that is designed to set up a web server. The playbook needs to assign a variable named `webserver_port` based on the operating system of the target host. The default port should be 80, but if the target host is running Ubuntu, the port should be set to 8080. Below is the pseudo code for the task:

Choose the correct statement regarding the execution of this task:

A: The task will fail because the comparison in the conditional statement is incorrect.
B: The task will assign port 8080 for all Debian-based distributions, including Ubuntu.
C: The task will always assign port 80, regardless of the operating system.
D: The task will assign port 8080 only if the `ansible_os_family` variable is exactly 'Ubuntu'.
E: The task will fail because `set_fact` does not support conditional assignments.
F: The task will assign port 8080 for Ubuntu and port 80 for all other operating systems.

You are given a Jenkinsfile for a pipeline that builds, tests, and deploys an application. The pipeline has multiple stages, and you need to optimize it by ensuring certain stages are executed only under specific conditions. The current Jenkinsfile looks like this:

Your task is to modify the Jenkinsfile so that:

1. The 'Test' stage is executed only if the 'Build' stage is successful.
2. The 'Deploy' stage is executed only for builds triggered by commits to the 'master' branch.
3. All stages should always run for scheduled nightly builds regardless of the branch.

Which of the following modifications to the Jenkinsfile will meet these requirements?

A Jenkins multibranch pipeline is configured to build projects from a version control system (VCS) with multiple branches. The pipeline is set up with specific build strategies to optimize resource usage and build times. The Jenkins administrator needs to ensure that the pipeline:

1. Automatically triggers builds for the 'master' and 'develop' branches upon new commits.
2. Does not automatically build feature branches but allows manual builds.
3. Automatically builds a branch if it has a pull request open with the 'master' branch.

Which combination of build strategies and configurations should the Jenkins administrator use?

A: Enable SCM polling, add a regular expression to include 'master' and 'develop', and use the Pull Request build strategy.
B: Use the Discover Branches strategy with filters for 'master' and 'develop', and the Pull Request build strategy with a target branch filter for 'master'.
C: Enable SCM polling with a cron expression, use a script to exclude feature branches, and add a webhook for pull request events.
D: Use the Discover Branches strategy, add a regular expression to exclude feature branches, and enable webhooks for pull request events.
E: Enable SCM polling for all branches, use the Discover Tags strategy, and add a post-receive hook in VCS for 'master' and 'develop'.
F: Use the Discover Branches strategy for all branches, add a property to manually trigger builds for feature branches, and use the Pull Request build strategy.

Consider a Jenkins Pipeline which includes a Jenkinsfile with an embedded Python script. The pipeline is designed for a multi-stage build process. The Python script is responsible for performing certain operations based on the current Jenkins build status. Analyze the following Jenkinsfile pseudo-code snippet:

The pipeline sets an environment variable `BUILD_STATUS` which can have values 'SUCCESS', 'FAILURE', or 'UNSTABLE'. What will be the output and the exit status of the Python script when `BUILD_STATUS` is set to 'UNSTABLE'?

As a senior DevOps engineer, you are tasked with diagnosing performance issues on a Linux server running Ubuntu 20.04. The server hosts several critical applications, but lately, users have been experiencing significant slowness. Initial monitoring shows that CPU and memory utilization are consistently high. To identify the root cause, you check the output of `top` and `ps` commands, which indicate that a particular process is consuming an unusually high amount of resources. However, the process name is generic and does not clearly indicate which application or service it belongs to. You also examine `/var/log/syslog` for any unusual entries but find nothing out of the ordinary. Based on this situation, which of the following steps would most effectively help you identify and resolve the performance issue?

A: Increase the server's physical memory and CPU capacity.
B: Use the `lsof` command to identify the files opened by the suspect process.
C: Reboot the server to reset all processes.
D: Examine the `/etc/hosts` file for any incorrect configurations.
E: Run the `netstat` command to check for abnormal network activity.
F: Check the crontab for any recently added scheduled tasks.

You are in charge of developing a Bash script for setting up a continuous integration pipeline for a web application. The source code is hosted in a Git repository. The script's goals include:

1. Ensuring the local copy of the repository in /var/www/html is updated to the latest version.
2. Creating a .env file with APP_ENV=production in the project root if it doesn't already exist.
3. Running a test suite with ./run_tests.sh and handling any test failures appropriately.
4. Logging the current timestamp and commit hash in deployment_log.txt in the project root if tests pass.

Which of the following script options would most effectively and safely accomplish these tasks?

Consider the following Dockerfile, which utilizes multistage builds. The aim is to build a lightweight, optimized image that just runs the application.

The Dockerfile first defines a base image that includes Node.js and npm, then it creates an intermediate image to install the npm dependencies. Afterwards, it runs the tests in another stage and finally, creates the release image.

Which of the following statements are true?

A: The final image will include the test scripts.
B: If a test fails, the final image will not be created.
C: The node_modules directory in the final image comes from the base image.
D: The final image will only contain the necessary application files and dependencies.
E: If the application's source code changes, only the release stage needs to be rebuilt.

You have two docker containers, X and Y. Container X is running a web service listening on port 8080, and container Y is supposed to consume this service. Both containers are created from images that don't have any special network configurations.

Container X has a Dockerfile as follows:

And, you build and run it with the following commands:

Container Y is also running alpine with python installed, and it's supposed to read data from the `/app/data` directory and send a GET request to `http://localhost:8080` every 5 minutes. The Dockerfile for container B is:

And you run it with:

Assuming all the python scripts work perfectly and firewall isn't blocking any connections, you find that container Y can't access the web service of container X via `http://localhost:8080` and also it can't read the data in `/app/data` directory. What could be the potential reason(s)?

A: Y can't access X's web service because they're in different Docker networks.
B: Y can't read the data because the volume is not shared correctly.
C: Both A and B are correct.
D: Both A and B are incorrect.

You have been asked to optimize a Dockerfile for a Python application that involves a heavy dependency installation. Here is the Dockerfile you are starting with:

Given that the application's source code changes frequently but the dependencies listed in requirements.txt rarely change, how can you optimize this Dockerfile to take advantage of Docker's layer caching, reducing the build time?

A: Move the `RUN pip install` command to before the `COPY` command.
B: Change `COPY . /app` to `COPY ./app.py /app` and move the `RUN pip install` command to before the `COPY` command.
C: Add `RUN pip cache purge` before `RUN pip install`.
D: Replace the base image with `python:3.8-slim`.
E: Implement multi-stage builds.

Check the following Dockerfile used for a project (STAGE 1):

We created an image from this Dockerfile on Dec 14 2021. A couple of weeks after Dec 14 2021, Ubuntu released new security updates to their repository. After 2 months, we modified the file (STAGE 2):

Couple of weeks later, we further modified the file to add a local file ada.txt to /ada.txt (STAGE 3): (Note that ada.txt exists in /home/adaface and the dockerfile exists in /home/code folders)

Pick correct statements:

A: If we run “docker build .” at STAGE 2, new Ubuntu updates will be fetched because apt-get update will be run again since cache is invalidated for all lines/layers of Dockerfile when a new line is added.
B: If we run “docker build .” at STAGE 2, new Ubuntu updates will not be fetched since cache is invalidated only for last two lines of the updated Dockerfile. Since the first two commands remain the same, cached layers are re-used skipping apt get update.
C: To skip Cache, “docker build -no-cache .” can be used at STAGE 2. This will ensure new Ubuntu updates are picked up.
D: Docker command “docker build .” at STAGE 3 works as expected and adds local file ada.txt to the image.
E: Docker command “docker build .” at STAGE 3 gives an error “no such file or directory” since /home/adaface/ada.txt is not part of the Dockerfile context.

Review the following Dockerfiles that work on two projects (project and project2):

All Docker files have the same end result:

- ‘project’ is cloned from git. After running few commands, ‘project’ code is removed.
- ‘project2’ is copied from file system and permissions to the folder is changed.

Pick the correct statements:

A: File 1 is the most efficient of all.
B: File 2 is the most efficient of all.
C: File 3 is the most efficient of all.
D: File 4 is the most efficient of all.
E: Merging multiple RUN commands into a single RUN command is efficient for ‘project’ since each RUN command creates a new layer with changed files and folders. Deleting files with RUN only marks these files as deleted but does not reclaim disk space. 
F: Copying ‘project2’ files and changing ownership in two separate commands will result in two layers since Docker duplicates all the files twice.