Deploy Memcached

This guide shows you how to use Memcached, an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

To run it, follow these steps:

1. Install the kraft CLI tool and a container runtime engine, e.g. Docker.

2. Clone the examples repository and cd into the examples/memcached/ directory:

git clone https://github.com/kraftcloud/examples
cd examples/memcached/

Make sure to log into KraftCloud by setting your token and a metro close to you. We use fra0 (Frankfurt, 🇩🇪) in this guide:

# Set KraftCloud access token
export KRAFTCLOUD_TOKEN=token
# Set metro to Frankfurt, DE
export KRAFTCLOUD_METRO=fra0

When done, invoke the following command to deploy this application on KraftCloud:

kraft cloud deploy -p 11211:11211/tls -M 256 .

The output shows the instance URL and other details:

[●] Deployed successfully!
 │
 ├────────── name: memcached-arkv7
 ├────────── uuid: da436eca-bc64-46d7-a04c-72832652b10e
 ├───────── state: running
 ├────────── fqdn: weathered-smoke-hehsdinv.fra0.kraft.host
 ├───────── image: memcached@sha256:f53cdbce4dc185e8acc8ecb93a0ab0ba99085ca0837a0ad2062aae9e31382e58
 ├───── boot time: 19.27 ms
 ├──────── memory: 256 MiB
 ├─ service group: weathered-smoke-hehsdinv
 ├── private fqdn: memcached-arkv7.internal
 ├──── private ip: 172.16.6.5
 └────────── args: /usr/bin/memcached -u root

In this case, the instance name is memcached-arkv7 and the service group is weathered-smoke-hehsdinv. They are different for each run.

To test the deployment, first forward the port with the kraft cloud tunnel command. Be sure to use the service group returned by the kraft cloud deploy command:

kraft cloud tunnel weathered-smoke-hehsdinv 11211:11211

Now, on a separate console, run the following commands to test that it works (you should see output when incrementing):

telnet 127.0.0.1 11211
set test 0 0 1
0
incr test 1
incr test 1

To exit telnet run:

Ctrl + ]
Ctrl + C

To disconnect, simply kill the tunnel command with ctrl-C

Note

We use kraft cloud tunnel only when a service doesn’t support TLS and is not HTTP-based (we use TLS/SNI to determine the correct instance to send traffic to). Also note that tunnel command is not needed when connecting via an instance’s private IP/FQDN, ie, when a Memcached instance is used as a backend to another instance that acts as a frontend and which does support TLS.

At any point in time, you can list information about the instance:

kraft cloud instance list

NAME             FQDN                               STATE    CREATED AT      IMAGE                            MEMORY   ARGS                             BOOT TIME
memcached-arkv7  weathered-smoke-hehsdinv.fra0....  running  11 minutes ago  memcached@sha256:f53cdbce4...    256 MiB  /usr/bin/memcached -u root       19266us

When done, you can remove the instance:

kraft cloud instance remove memcached-arkv7

Customize your Application

To customize the application, update the files in the repository, listed below:

• Kraftfile: the KraftCloud specification, including command-line arguments
• Dockerfile: In case you need to add files to your instance’s rootfs

Kraftfile

spec: v0.6

runtime: memcached:latest

rootfs: ./Dockerfile

cmd: ["/usr/bin/memcached", "-u", "root"]

Dockerfile

FROM debian:bookworm AS build

RUN set -xe; \
    echo "Your code here";

FROM scratch

# Your files here
# COPY --from=build / /

Learn More

Use the --help option for detailed information on using KraftCloud:

kraft cloud --help

Or visit the CLI Reference.