Installation and setup in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the first step to install Elasticsearch on your machine?

Download the Elasticsearch package from the official website or use a package manager suitable for your operating system.

beginner

Which command starts the Elasticsearch service after installation?

You can start Elasticsearch by running ./bin/elasticsearch from the installation directory or using system service commands like systemctl start elasticsearch on Linux.

beginner

Why is it important to check Java version before installing Elasticsearch?

Elasticsearch requires a compatible Java version to run. Checking ensures your system has the right Java environment to avoid errors during startup.

intermediate

What file do you edit to configure Elasticsearch settings after installation?

You edit the elasticsearch.yml file located in the config folder to change settings like cluster name, network host, and ports.

beginner

How can you verify that Elasticsearch is running correctly after setup?

Open a browser or use a tool like curl to access http://localhost:9200. You should see a JSON response with cluster information.

What port does Elasticsearch use by default?

A 8080

B 5432

C 3306

D 9200

Elasticsearch listens on port 9200 by default for HTTP requests.

Which file contains the main configuration for Elasticsearch?

A elasticsearch.yml

B config.json

C settings.xml

D elasticsearch.conf

The elasticsearch.yml file holds the main configuration settings.

Which command starts Elasticsearch on Linux using systemd?

A systemctl start elasticsearch

B service elasticsearch stop

C start elasticsearch

D elasticsearch run

The systemctl start elasticsearch command starts the service on Linux systems using systemd.

Before installing Elasticsearch, you should verify your system has:

A Node.js installed

B Compatible Java version

C Python installed

D Docker installed

Elasticsearch requires a compatible Java version to run properly.

How do you check if Elasticsearch is running after setup?

A Run 'java -version'

B Open http://localhost:8080

C Access http://localhost:9200 in a browser

D Check the Docker container logs

Accessing http://localhost:9200 returns cluster info if Elasticsearch is running.

Describe the basic steps to install and start Elasticsearch on your computer.

Think about downloading, prerequisites, starting, and checking.

Explain how to configure Elasticsearch after installation.

Focus on the configuration file and restarting.

Practice

1. What is the first step to install Elasticsearch on your computer?

easy

A. Run the Elasticsearch service

B. Configure the Elasticsearch index

C. Access http://localhost:9200/ to test

D. Download and extract the Elasticsearch package

Solution

1. Step 1: Understand the installation process

   The first step is to get the Elasticsearch files by downloading and extracting them to your machine.

2. Step 2: Recognize the order of setup steps

   Running the service and testing come after downloading and extracting the files.

3. Final Answer:

   Download and extract the Elasticsearch package -> Option D

4. Quick Check:

   First step = Download and extract [OK]

Hint: Start by getting the files before running anything [OK]

Common Mistakes:

• Trying to run Elasticsearch before downloading
• Testing setup before starting the service
• Configuring index before installation

2. Which command correctly starts Elasticsearch on a Unix-like system after installation?

easy

A. ./bin/elasticsearch

B. start elasticsearch

C. run elasticsearch.exe

D. elasticsearch start

Solution

1. Step 1: Identify the correct executable path

   On Unix-like systems, Elasticsearch is started by running the executable in the 'bin' folder with './bin/elasticsearch'.

2. Step 2: Eliminate incorrect commands

   Commands like 'start elasticsearch' or 'elasticsearch start' are not valid shell commands for starting Elasticsearch directly.

3. Final Answer:

   ./bin/elasticsearch -> Option A

4. Quick Check:

   Unix start command = ./bin/elasticsearch [OK]

Hint: Use ./bin/elasticsearch to start on Unix systems [OK]

Common Mistakes:

• Using Windows commands on Unix
• Omitting './' before the executable
• Trying to run non-existent commands

3. After starting Elasticsearch, what is the expected output of running curl http://localhost:9200/?

medium

A. {"name":"your-node-name","cluster_name":"elasticsearch","version":{"number":"8.0.0"},"tagline":"You Know, for Search"}

B. Error: Connection refused

C. 404 Not Found

D. Elasticsearch service stopped

Solution

1. Step 1: Understand the curl command purpose

   The curl command requests the root URL of Elasticsearch, which returns JSON with node and cluster info.

2. Step 2: Recognize the expected JSON response

   The response includes keys like 'name', 'cluster_name', 'version', and 'tagline' confirming the service is running.

3. Final Answer:

   {"name":"your-node-name","cluster_name":"elasticsearch","version":{"number":"8.0.0"},"tagline":"You Know, for Search"} -> Option A

4. Quick Check:

   curl root URL returns JSON info [OK]

Hint: curl localhost:9200 returns JSON if Elasticsearch runs [OK]

Common Mistakes:

• Expecting plain text instead of JSON
• Not starting Elasticsearch before curl
• Using wrong URL or port

4. You tried to start Elasticsearch but got the error: "Address already in use". What is the most likely cause?

medium

A. You did not download the package

B. Elasticsearch is not installed

C. Another service is using port 9200

D. Your firewall is blocking Elasticsearch

Solution

1. Step 1: Interpret the error message

   "Address already in use" means the network port Elasticsearch wants to use (default 9200) is busy.

2. Step 2: Identify the cause of port conflict

   Another program or service is likely running on port 9200, preventing Elasticsearch from binding to it.

3. Final Answer:

   Another service is using port 9200 -> Option C

4. Quick Check:

   Port conflict error = Another service using port [OK]

Hint: Check if port 9200 is busy before starting Elasticsearch [OK]

Common Mistakes:

• Assuming Elasticsearch is not installed
• Ignoring port conflicts
• Blaming firewall without checking ports

5. You want to automate testing if Elasticsearch is running after setup. Which script snippet correctly checks the service by using curl and exits with code 0 if successful?

hard

A. curl http://localhost:9200/ && echo 'Running' || echo 'Stopped'

B. curl -s http://localhost:9200/ | grep -q 'You Know, for Search' && exit 0 || exit 1

C. curl -X POST http://localhost:9200/ && exit 0

D. curl http://localhost:9200/_search && exit 1

Solution

1. Step 1: Understand the test goal

   The script should silently check Elasticsearch root URL and confirm the expected tagline text.

2. Step 2: Analyze each option's behavior

   curl -s http://localhost:9200/ | grep -q 'You Know, for Search' && exit 0 || exit 1 uses curl quietly (-s), searches for the tagline, and exits 0 if found, else 1. This correctly tests service availability.

3. Final Answer:

   curl -s http://localhost:9200/ | grep -q 'You Know, for Search' && exit 0 || exit 1 -> Option B

4. Quick Check:

   Silent curl + grep tagline + exit code 0 if found [OK]

Hint: Use curl with grep for tagline, exit 0 if found [OK]

Common Mistakes:

• Using POST instead of GET for root URL
• Not checking output content
• Exiting with wrong code on success