In this article, we will learn how to effectively monitor Memcached, a widely used in-memory key-value store for caching data in distributed systems. Monitoring its the performance and health is essential for ensuring the optimal operation of applications that depend on it. To achieve this, we’ll leverage the combined power of Prometheus, a robust monitoring and alerting toolkit, and Grafana, a versatile visualization platform. Together, these tools offer a comprehensive solution for monitoring Memcached.
Table of Contents
Prerequisites
- AWS Account with Ubuntu 22.04 LTS EC2 Instance.
- Basic knowledge of AWS services, Prometheus and Grafana.
Step #1:Install Memcached on Ubuntu
First update the package repository.
sudo apt update 
Install the memcached using following command.
sudo apt install memcached
Step #2:Install Prometheus on Ubuntu
Download the latest version of Prometheus from the GitHub repository using the following command.
wget https://github.com/prometheus/prometheus/releases/download/v2.30.0/prometheus-2.30.0.linux-amd64.tar.gz
After downloading the latest version of Prometheus binary, extract the downloaded archives.
tar xvfz prometheus-2.30.0.linux-amd64.tar.gzThe command extracts the contents of the file prometheus-2.30.0.linux-amd64.tar.gz
now navigate to the extracted directory using following command.
cd prometheus-2.30.0.linux-amd64
navigate to the /etc/systemd/system, this is where typically systemd unit files are located, which are used for managing services on Linux systems.
cd /etc/systemd/system
now lets create a service for Prometheus named prometheus.service.
sudo vi prometheus.service
add the following content into it.
[Unit]
Description=Prometheus
Wants=network-online.target
After=network-online.target
[Service]
ExecStart=/home/ubuntu/prometheus-2.30.0.linux-amd64/prometheus --config.file=/home/ubuntu/prometheus-2.30.0.linux-amd64/prometheus.yml
Restart=always
[Install]
WantedBy=default.target
save the file and close it.
Now our prometheus.service is created. After this reload the daemon service.
sudo systemctl daemon-reload
enable the Prometheus service.
sudo systemctl enable prometheus.service
And start the Prometheus service.
sudo systemctl start prometheus.service
now Verify the status of the Prometheus service using following command:
sudo systemctl status prometheus.service
If your service is running properly then you can run prometheus by running
Public IP:9090 which is default port for prometheus in url.
Step #3:Install Grafana on Ubuntu
First import the GPG key used by the Grafana package.
wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
then add the Grafana repository to the APT sources.
sudo add-apt-repository "deb https://packages.grafana.com/oss/deb stable main"
After adding the repository update the package lists.
sudo apt update
Once updating of package lists is complete, install the grafana.
sudo apt install grafana
Start the Grafana service.
sudo systemctl start grafana-server
Enable the Grafana service.
sudo systemctl enable grafana-server
and if everything works fine and your service is running properly then run grafana by running your Public IP:3000 which is default port of grafana in searchbar.
you will see the login page of grafana (UI) user interface
Grafana has admin as default username and password.
it will ask for changing the password you can change it or skip the procedure.
then you will see the welcome page of grafana.
Step #4:Create User Group and User for Prometheus
Now after the installation of Prometheus and grafana is done lets create User Group and User for Prometheus.
sudo groupadd --system prometheus
sudo useradd -s /sbin/nologin --system -g prometheus prometheus
Step #5:Download and Install Memcached Exporter
Download the Memcached Exporter binary.
curl -s https://api.github.com/repos/prometheus/memcached_exporter/releases/latest | grep browser_download_url | grep linux-amd64 | cut -d '"' -f 4 | wget -qi -
Extract the downloaded archive file.
tar xvf memcached_exporter-*.linux-amd64.tar.gz
Move the binary to the appropriate directory.
sudo mv memcached_exporter-*.linux-amd64/memcached_exporter /usr/local/bin/
Confirm the installation of the exporter by running the following command.
memcached_exporter --version
Step #6: Configuring Memcached Exporter Service
Create a service file.
sudo vim /etc/systemd/system/memcached_exporter.service
Add the following content to the service file.
[Unit]
Description=Prometheus Memcached Exporter
Documentation=https://github.com/prometheus/memcached_exporter
Wants=network-online.target
After=network-online.target
[Service]
Type=simple
User=prometheus
Group=prometheus
ExecReload=/bin/kill -HUP $MAINPID
ExecStart=/usr/local/bin/memcached_exporter
SyslogIdentifier=memcached_exporter
Restart=always
[Install]
WantedBy=multi-user.target
Save the file and verify that the configuration is correct.
sudo systemctl daemon-reload
Enable and start the service.
sudo systemctl enable memcached_exporter
sudo systemctl start memcached_exporter
Confirm the service status.
systemctl status memcached_exporter
You can run the Public IP:9150 To view its web page.
Step #7:Configuring Memcached Exporter Endpoint in Prometheus Configuration
Navigate to the directory containing the Prometheus configuration file.
cd prometheus-2.30.0.linux-amd64
Edit the prometheus.yml file.
nano prometheus.yml
add the following block into it.
# my global config
global:
scrape_interval: 15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
# scrape_timeout is set to the global default (10s).
# Alertmanager configuration
alerting:
alertmanagers:
- static_configs:
- targets:
# - alertmanager:9093
# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
rule_files:
# - "first_rules.yml"
# - "second_rules.yml"
# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
# The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
- job_name: "prometheus"
# metrics_path defaults to '/metrics'
# scheme defaults to 'http'.
static_configs:
- targets: ["localhost:9090"]
#Memcached Servers
- job_name: "memcached"
static_configs:
- targets: ["localhost:9150"]
save the file and close it.
restart the Prometheus service.
sudo systemctl restart prometheus.service
Now go to Prometheus dashboard and click on status, select target, you can see our exporter are up and running.
Step #8:Setting up Grafana Dashboards for memcached Metrics
Now go back to the Grafana welcome page. Go to the Home in the left top corner.
Then go to the Connections and select the Data sources option.
Search for Prometheus in the search bar and select it.
In connection, in Prometheus server URL, give the server url on which our prometheus is running.
after this click on save and test button. You will see the message for prometheus being successfully queried.
now go to the ‘+‘ icon from up-right corner and select the New dashboard option
Here you can start your own new dashboard by adding a visualization.
So click on + Add visualization option button.
Here you can also import dashboards.
Select the Prometheus as Data source.
You will see the edit panel page.
Now in the Query section add the A query
- Metric: memcached_process_system_cpu_seconds_total
- job: memcached
then add the B query
- Metric: memcached_process_user_cpu_seconds_total
- job: memcached
Click on run queries You will see the following output.
It’s in the Time series visualization, but there are many visualization option like Guage, stats, Bar graph etc.
Click ctrl+s to save the file. Give an appropriate Title for your dashboard the save it.
Conclusion:
In conclusion, today we’ve learned how to set up monitoring for Memcached using Prometheus and Grafana. Monitoring Memcached metrics allows you to gain insights into its performance, troubleshoot issues, and ensure the efficient operation of your caching infrastructure. With Prometheus collecting metrics and Grafana providing visualization capabilities, you have a powerful monitoring solution at your disposal to keep your Memcached instances running smoothly.
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