DevOps Test

What will the following Python code output?

The function high_sess should compute the highest number of events per session of each user in the database by reading a comma-separated value input file of session data. The result should be returned from the function as a dictionary. The first column of each line in the input file is expected to contain the user’s name represented as a string. The second column is expected to contain an integer representing the events in a session. Here is an example input file:

Tony,10
Stark,12
Black,25
Your program should ignore a non-conforming line like this one.
Stark,3
Widow,6
Widow,14

The resulting return value for this file should be the following dictionary: { 'Stark':12, 'Black':25, 'Tony':10, 'Widow':14 }

What should replace the CODE TO FILL line to complete the function?

Below are code lines to create a Python function. Ignoring indentation, what lines should be used and in what order for the following function to be complete:

Consider the following Python code:

In the above code, recursive_search is a function that takes a dictionary (data) and a target key (target) as arguments. It searches for the target key within the dictionary, which could potentially have nested dictionaries and lists as values, and returns the value associated with the target key. If the target key is not found, it returns None.

nested_dict is a dictionary that contains multiple levels of nested dictionaries and lists. The recursive_search function is then called with nested_dict as the data and 'target_key' as the target.

What will the output be after executing the above code?

What does the below function ‘fun’ does?

A: Sum of digits of the number passed to fun.
B: Number of digits of the number passed to fun.
C: 0 if the number passed to fun is divisible by 10. 1 otherwise.
D: Sum of all digits number passed to fun except for the last digit.

You are working on a Linux system and have recently installed a new program named myprogram. The executable is located in /opt/myprogram/bin/. You want to be able to run this program from any directory in your shell without specifying the full path.

You executed the following command:
export PATH="/opt/myprogram/bin"

However, when you try to run the program using myprogram, you get the following error message:
-bash: myprogram: command not found

Which of the following commands can fix this issue and allow you to run the program?

A: export PATH=$PATH:/opt/myprogram/bin/
B: export PATH="/opt/myprogram:$PATH"
C: export PATH="/opt/myprogram/bin:$PATH"
D: ln -s /opt/myprogram/bin/myprogram /usr/local/bin/myprogram

Consider the following directory structure:

You start at /home/user and execute the following commands:

What will be the resulting directory structure?

How many times will the following code will print "Mellow Yellow"?

Our software engineering intern, Wu is looking to use port 4545 on localhost to connect to a remote server called woot.bananas.com on port 80. Which command would you recommend for this?

Suppose a remote repository is cloned in local system and a old file named “modified_file” is modified and now if following command is run, what will "git status" return?

Which of the following commands will merge dev-fixes into the master-live branch?

a. git checkout master-live and git merge dev-fixes
b. git checkout dev-fixes and git merge master-live
c. git merge master-live and git checkout dev-fixes
d. git merge dev-fixes and git checkout master-live

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.

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?