Grafana dashboards for containers in Docker - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Docker command for Grafana container logs?

You run the command docker logs grafana_container --tail 3. The last three log lines are:

t=2024-06-01T12:00:00Z lvl=info msg="Starting Grafana"
t=2024-06-01T12:00:01Z lvl=info msg="HTTP Server Listen"
t=2024-06-01T12:00:02Z lvl=warn msg="Data source not found"

What will be the exact output of the command?

Docker

docker logs grafana_container --tail 3

A

Starting Grafana
HTTP Server Listen
Data source not found

B

t=2024-06-01T12:00:00Z lvl=info msg="Starting Grafana"
t=2024-06-01T12:00:01Z lvl=info msg="HTTP Server Listen"
t=2024-06-01T12:00:02Z lvl=warn msg="Data source not found"

C Error: No such container: grafana_container

D

t=2024-06-01T12:00:00Z lvl=info msg="Starting Grafana"
t=2024-06-01T12:00:01Z lvl=info msg="HTTP Server Listen"

💡 Hint

The --tail option limits the number of log lines shown, but the output includes full log lines.

The command shows the last 3 log lines exactly as they appear in the container logs. Option B matches all three lines with timestamps and levels.

❓ Configuration

intermediate

Which Docker Compose snippet correctly sets up Grafana with Prometheus as a data source?

You want to run Grafana and Prometheus containers together. Grafana should connect to Prometheus at http://prometheus:9090. Which Docker Compose service configuration for Grafana is correct?

Docker

version: '3.8'
services:
  prometheus:
    image: prom/prometheus
    ports:
      - 9090:9090
  grafana:
    image: grafana/grafana
    ports:
      - 3000:3000
    environment:
      - GF_SECURITY_ADMIN_PASSWORD=admin
    depends_on:
      - prometheus
    # Which environment variable below correctly sets Prometheus as data source URL?

A

environment:
  - GF_DATASOURCE_PROMETHEUS_URL=http://prometheus:9090

B

environment:
  - GF_SECURITY_ADMIN_USER=prometheus

C

environment:
  - GF_DATASOURCE_URL=http://prometheus:9090

D

environment:
  - GF_SERVER_HTTP_PORT=9090

💡 Hint

Grafana uses environment variables starting with GF_DATASOURCE_ to configure data sources.

The correct environment variable to set Prometheus URL as a data source is GF_DATASOURCE_PROMETHEUS_URL. Option A sets this correctly.

🔀 Workflow

advanced

What is the correct order to create a Grafana dashboard for Docker container metrics?

Arrange these steps in the correct order to set up a Grafana dashboard that shows Docker container CPU and memory usage:

A 3,1,2,4

B 2,1,3,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

You need data collection before adding data source and dashboards.

First, Prometheus with Docker metrics exporter must run to collect data. Then add Prometheus as Grafana data source. Next create dashboard and add panels with queries.

❓ Troubleshoot

advanced

Why does Grafana show 'Data source not found' error for Prometheus?

You have Grafana and Prometheus running in Docker containers. Grafana shows an error: Data source not found when trying to load Prometheus metrics. Which is the most likely cause?

A Grafana admin password is incorrect

B Grafana container port 3000 is not exposed

C Prometheus container is not running or unreachable from Grafana container

D Prometheus is running but has no metrics to serve

💡 Hint

Grafana needs network access to Prometheus to find the data source.

If Prometheus is not running or Grafana cannot reach it, Grafana will show 'Data source not found'. Other options do not cause this error.

✅ Best Practice

expert

Which practice is best for maintaining Grafana dashboards for multiple Docker environments?

You manage Grafana dashboards for several Docker environments (dev, staging, production). What is the best practice to keep dashboards consistent and easy to update?

A Export dashboards as JSON files and manage them with version control

B Manually edit dashboards in Grafana UI for each environment

C Use different Grafana instances with separate dashboards for each environment

D Store dashboards only inside Docker container volumes without backups

💡 Hint

Think about automation and tracking changes.

Exporting dashboards as JSON and managing them with version control allows easy updates, sharing, and rollback. Manual edits or no backups risk inconsistency and loss.