437 lines
20 KiB
Markdown
437 lines
20 KiB
Markdown
# Bitnami package for Memcached
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## What is Memcached?
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> Memcached is an high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.
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[Overview of Memcached](https://memcached.org)
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Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.
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## TL;DR
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```console
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docker run --name memcached bitnami/memcached:latest
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```
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## ⚠️ Important Notice: Upcoming changes to the Bitnami Catalog
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Beginning August 28th, 2025, Bitnami will evolve its public catalog to offer a curated set of hardened, security-focused images under the new [Bitnami Secure Images initiative](https://news.broadcom.com/app-dev/broadcom-introduces-bitnami-secure-images-for-production-ready-containerized-applications). As part of this transition:
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- Granting community users access for the first time to security-optimized versions of popular container images.
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- Bitnami will begin deprecating support for non-hardened, Debian-based software images in its free tier and will gradually remove non-latest tags from the public catalog. As a result, community users will have access to a reduced number of hardened images. These images are published only under the “latest” tag and are intended for development purposes
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- Starting August 28th, over two weeks, all existing container images, including older or versioned tags (e.g., 2.50.0, 10.6), will be migrated from the public catalog (docker.io/bitnami) to the “Bitnami Legacy” repository (docker.io/bitnamilegacy), where they will no longer receive updates.
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- For production workloads and long-term support, users are encouraged to adopt Bitnami Secure Images, which include hardened containers, smaller attack surfaces, CVE transparency (via VEX/KEV), SBOMs, and enterprise support.
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These changes aim to improve the security posture of all Bitnami users by promoting best practices for software supply chain integrity and up-to-date deployments. For more details, visit the [Bitnami Secure Images announcement](https://github.com/bitnami/containers/issues/83267).
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## Why use Bitnami Secure Images?
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- Bitnami Secure Images and Helm charts are built to make open source more secure and enterprise ready.
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- Triage security vulnerabilities faster, with transparency into CVE risks using industry standard Vulnerability Exploitability Exchange (VEX), KEV, and EPSS scores.
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- Our hardened images use a minimal OS (Photon Linux), which reduces the attack surface while maintaining extensibility through the use of an industry standard package format.
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- Stay more secure and compliant with continuously built images updated within hours of upstream patches.
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- Bitnami containers, virtual machines and cloud images use the same components and configuration approach - making it easy to switch between formats based on your project needs.
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- Hardened images come with attestation signatures (Notation), SBOMs, virus scan reports and other metadata produced in an SLSA-3 compliant software factory.
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Only a subset of BSI applications are available for free. Looking to access the entire catalog of applications as well as enterprise support? Try the [commercial edition of Bitnami Secure Images today](https://www.arrow.com/globalecs/uk/products/bitnami-secure-images/).
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## How to deploy Memcached in Kubernetes?
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Deploying Bitnami applications as Helm Charts is the easiest way to get started with our applications on Kubernetes. Read more about the installation in the [Bitnami Memcached Chart GitHub repository](https://github.com/bitnami/charts/tree/master/bitnami/memcached).
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## Why use a non-root container?
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Non-root container images add an extra layer of security and are generally recommended for production environments. However, because they run as a non-root user, privileged tasks are typically off-limits. Learn more about non-root containers [in our docs](https://techdocs.broadcom.com/us/en/vmware-tanzu/application-catalog/tanzu-application-catalog/services/tac-doc/apps-tutorials-work-with-non-root-containers-index.html).
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## Supported tags and respective `Dockerfile` links
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Learn more about the Bitnami tagging policy and the difference between rolling tags and immutable tags [in our documentation page](https://techdocs.broadcom.com/us/en/vmware-tanzu/application-catalog/tanzu-application-catalog/services/tac-doc/apps-tutorials-understand-rolling-tags-containers-index.html).
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You can see the equivalence between the different tags by taking a look at the `tags-info.yaml` file present in the branch folder, i.e `bitnami/ASSET/BRANCH/DISTRO/tags-info.yaml`.
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Subscribe to project updates by watching the [bitnami/containers GitHub repo](https://github.com/bitnami/containers).
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## Get this image
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The recommended way to get the Bitnami Memcached Docker Image is to pull the prebuilt image from the [Docker Hub Registry](https://hub.docker.com).
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```console
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docker pull bitnami/memcached:latest
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```
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To use a specific version, you can pull a versioned tag. You can view the [list of available versions](https://hub.docker.com/r/bitnami/memcached/tags/) in the Docker Hub Registry.
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```console
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docker pull bitnami/memcached:[TAG]
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```
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If you wish, you can also build the image yourself by cloning the repository, changing to the directory containing the Dockerfile and executing the `docker build` command. Remember to replace the `APP`, `VERSION` and `OPERATING-SYSTEM` path placeholders in the example command below with the correct values.
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```console
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git clone https://github.com/bitnami/containers.git
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cd bitnami/APP/VERSION/OPERATING-SYSTEM
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docker build -t bitnami/APP:latest .
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```
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## Connecting to other containers
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Using [Docker container networking](https://docs.docker.com/engine/userguide/networking/), a Memcached server running inside a container can easily be accessed by your application containers.
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Containers attached to the same network can communicate with each other using the container name as the hostname.
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### Using the Command Line
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#### Step 1: Create a network
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```console
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docker network create app-tier --driver bridge
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```
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#### Step 2: Launch the Memcached server instance
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Use the `--network app-tier` argument to the `docker run` command to attach the Memcached container to the `app-tier` network.
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```console
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docker run -d --name memcached-server \
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--network app-tier \
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bitnami/memcached:latest
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```
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#### Step 3: Launch your application container
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```console
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docker run -d --name myapp \
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--network app-tier \
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YOUR_APPLICATION_IMAGE
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```
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> **IMPORTANT**:
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>
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> 1. Please update the **YOUR_APPLICATION_IMAGE_** placeholder in the above snippet with your application image
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> 2. In your application container, use the hostname `memcached-server` to connect to the Memcached server
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### Using a Docker Compose file
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When not specified, Docker Compose automatically sets up a new network and attaches all deployed services to that network. However, we will explicitly define a new `bridge` network named `app-tier`. In this example we assume that you want to connect to the Memcached server from your own custom application image which is identified in the following snippet by the service name `myapp`.
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```yaml
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version: '2'
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networks:
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app-tier:
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driver: bridge
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services:
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memcached:
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image: bitnami/memcached:latest
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networks:
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- app-tier
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myapp:
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image: YOUR_APPLICATION_IMAGE
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networks:
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- app-tier
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```
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> **IMPORTANT**:
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>
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> 1. Please update the **YOUR_APPLICATION_IMAGE_** placeholder in the above snippet with your application image
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> 2. In your application container, use the hostname `memcached` to connect to the Memcached server
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Launch the containers using:
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```console
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docker-compose up -d
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```
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## Configuration
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### Environment variables
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#### Customizable environment variables
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| Name | Description | Default Value |
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|-----------------------------|------------------------------------------------------------------------|---------------|
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| `MEMCACHED_LISTEN_ADDRESS` | Host that the Memcached service will bind to. | `nil` |
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| `MEMCACHED_PORT_NUMBER` | Port number used by Memcached. | `11211` |
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| `MEMCACHED_USERNAME` | Memcached admin username. | `root` |
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| `MEMCACHED_PASSWORD` | Password for the Memcached admin user. | `nil` |
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| `MEMCACHED_MAX_ITEM_SIZE` | Memcached maximum item size. | `nil` |
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| `MEMCACHED_EXTRA_FLAGS` | Extra flags to be used when running Memcached. | `nil` |
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| `MEMCACHED_MAX_TIMEOUT` | Maximum timeout in seconds for Memcached to start or stop. | `5` |
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| `MEMCACHED_CACHE_SIZE` | Memcached cache size in MB. | `nil` |
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| `MEMCACHED_MAX_CONNECTIONS` | Maximum amount of concurrent connections that Memcached will tolerate. | `nil` |
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| `MEMCACHED_THREADS` | Amount of process threads that Memcached will use. | `nil` |
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#### Read-only environment variables
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| Name | Description | Value |
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|------------------------------|---------------------------------------------|--------------------------------------|
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| `MEMCACHED_BASE_DIR` | Memcached installation directory. | `${BITNAMI_ROOT_DIR}/memcached` |
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| `MEMCACHED_CONF_DIR` | Memcached configuration directory. | `${MEMCACHED_BASE_DIR}/conf` |
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| `MEMCACHED_DEFAULT_CONF_DIR` | Memcached configuration directory. | `${MEMCACHED_BASE_DIR}/conf.default` |
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| `MEMCACHED_BIN_DIR` | Memcached directory for binary executables. | `${MEMCACHED_BASE_DIR}/bin` |
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| `SASL_CONF_PATH` | Memcached SASL configuration directory. | `${MEMCACHED_CONF_DIR}/sasl2` |
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| `SASL_CONF_FILE` | Memcached SASL configuration | `${SASL_CONF_PATH}/memcached.conf` |
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| `SASL_DB_FILE` | Memcached SASL database file. | `${SASL_CONF_PATH}/memcachedsasldb` |
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| `MEMCACHED_DAEMON_USER` | Memcached system user. | `memcached` |
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| `MEMCACHED_DAEMON_GROUP` | Memcached system group. | `memcached` |
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### Specify the cache size
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By default, the Bitnami Memcached container will not specify any cache size and will start with Memcached defaults (64MB). You can specify a different value with the `MEMCACHED_CACHE_SIZE` environment variable (in MB).
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```console
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docker run --name memcached -e MEMCACHED_CACHE_SIZE=128 bitnami/memcached:latest
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```
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or by modifying the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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services:
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memcached:
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...
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environment:
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- MEMCACHED_CACHE_SIZE=128
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...
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```
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### Specify maximum number of concurrent connections
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By default, the Bitnami Memcached container will not specify any maximum number of concurrent connections and will start with Memcached defaults (1024 concurrent connections). You can specify a different value with the `MEMCACHED_MAX_CONNECTIONS` environment variable.
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```console
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docker run --name memcached -e MEMCACHED_MAX_CONNECTIONS=2000 bitnami/memcached:latest
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```
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or by modifying the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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services:
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memcached:
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...
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environment:
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- MEMCACHED_MAX_CONNECTIONS=2000
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...
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```
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### Specify number of threads to process requests
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By default, the Bitnami Memcached container will not specify the amount of threads for which to process requests for and will start with Memcached defaults (4 threads). You can specify a different value with the `MEMCACHED_THREADS` environment variable.
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```console
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docker run --name memcached -e MEMCACHED_THREADS=4 bitnami/memcached:latest
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```
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or by modifying the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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services:
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memcached:
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...
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environment:
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- MEMCACHED_THREADS=4
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...
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```
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### Specify max item size (slab size)
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By default, the Memcached container will not specify any max item size and will start with Memcached defaults (1048576 ~ 1 megabyte). You can specify a different value with the `MEMCACHED_MAX_ITEM_SIZE` environment variable. Only numeric values are accepted - use `8388608` instead of `8m`
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```console
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docker run --name memcached -e MEMCACHED_MAX_ITEM_SIZE=8388608 bitnami/memcached:latest
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```
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or by modifying the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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services:
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memcached:
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...
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environment:
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- MEMCACHED_MAX_ITEM_SIZE=8388608
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...
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```
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### Creating the Memcached admin user
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Authentication on the Memcached server is disabled by default. To enable authentication, specify the password for the Memcached admin user using the `MEMCACHED_PASSWORD` environment variable (or in the content of the file specified in `MEMCACHED_PASSWORD_FILE`).
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To customize the username of the Memcached admin user, which defaults to `root`, the `MEMCACHED_USERNAME` variable should be specified.
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```console
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docker run --name memcached \
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-e MEMCACHED_USERNAME=my_user \
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-e MEMCACHED_PASSWORD=my_password \
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bitnami/memcached:latest
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```
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or by modifying the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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version: '2'
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services:
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memcached:
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...
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environment:
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- MEMCACHED_USERNAME=my_user
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- MEMCACHED_PASSWORD=my_password
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...
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```
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> The default value of the `MEMCACHED_USERNAME` is `root`.
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### Passing extra command-line flags to memcached
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Passing extra command-line flags to the Memcached service command is possible by adding them as arguments to *run.sh* script:
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```console
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docker run --name memcached bitnami/memcached:latest /opt/bitnami/scripts/memcached/run.sh -vvv
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```
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Alternatively, modify the [`docker-compose.yml`](https://github.com/bitnami/containers/blob/main/bitnami/memcached/docker-compose.yml) file present in this repository:
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```yaml
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services:
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memcached:
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...
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command: /opt/bitnami/scripts/memcached/run.sh -vvv
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...
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```
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Refer to the [Memcached man page](https://www.unix.com/man-page/linux/1/memcached/) for the complete list of arguments.
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### Using custom SASL configuration
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In order to load your own SASL configuration file, you will have to make them available to the container. You can do it doing the following:
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- Mounting a volume with your custom configuration
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- Adding custom configuration via environment variable.
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By default, when authentication is enabled the SASL configuration of Memcached is written to `/opt/bitnami/memcached/sasl2/memcached.conf` file with the following content:
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```config
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mech_list: plain
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sasldb_path: /opt/bitnami/memcached/conf/memcachedsasldb
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```
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The `/opt/bitnami/memcached/conf/memcachedsasldb` is the path to the sasldb file that contains the list of Memcached users.
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### FIPS configuration in Bitnami Secure Images
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The Bitnami Memcached Docker image from the [Bitnami Secure Images](https://www.arrow.com/globalecs/uk/products/bitnami-secure-images/) catalog includes extra features and settings to configure the container with FIPS capabilities. You can configure the next environment variables:
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- `OPENSSL_FIPS`: whether OpenSSL runs in FIPS mode or not. `yes` (default), `no`.
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## Logging
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The Bitnami Memcached Docker image sends the container logs to the `stdout`. To view the logs:
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```console
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docker logs memcached
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```
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or using Docker Compose:
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```console
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docker-compose logs memcached
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```
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You can configure the containers [logging driver](https://docs.docker.com/engine/admin/logging/overview/) using the `--log-driver` option if you wish to consume the container logs differently. In the default configuration docker uses the `json-file` driver.
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## Maintenance
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### Upgrade this image
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Bitnami provides up-to-date versions of Memcached, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.
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#### Step 1: Get the updated image
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```console
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docker pull bitnami/memcached:latest
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```
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or if you're using Docker Compose, update the value of the image property to
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`bitnami/memcached:latest`.
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#### Step 2: Remove the currently running container
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```console
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docker rm -v memcached
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```
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or using Docker Compose:
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```console
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docker-compose rm -v memcached
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```
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#### Step 3: Run the new image
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Re-create your container from the new image.
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```console
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docker run --name memcached bitnami/memcached:latest
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```
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or using Docker Compose:
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```console
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docker-compose up memcached
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```
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## Notable Changes
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### 1.5.18-debian-9-r13 and 1.5.19-ol-7-r1
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- Fixes regression in Memcached Authentication introduced in release `1.5.18-debian-9-r6` and `1.5.18-ol-7-r7` (#62).
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### 1.5.18-debian-9-r6 and 1.5.18-ol-7-r7
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- Decrease the size of the container. The configuration logic is now based on Bash scripts in the `rootfs/ folder.
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- Custom SASL configuration should be mounted at `/opt/bitnami/memcached/conf/sasl2/` instead of `/bitnami/memcached/conf/`.
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- Password for Memcached admin user can be specified in the content of the file specified in `MEMCACHED_PASSWORD_FILE`.
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### 1.5.0-r1
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- The memcached container has been migrated to a non-root container approach. Previously the container run as `root` user and the memcached daemon was started as `memcached` user. From now own, both the container and the memcached daemon run as user `1001`.
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As a consequence, the configuration files are writable by the user running the memcached process.
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### 1.4.25-r4
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- `MEMCACHED_USER` parameter has been renamed to `MEMCACHED_USERNAME`.
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### 1.4.25-r0
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- The logs are always sent to the `stdout` and are no longer collected in the volume.
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## Using `docker-compose.yaml`
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Please be aware this file has not undergone internal testing. Consequently, we advise its use exclusively for development or testing purposes. For production-ready deployments, we highly recommend utilizing its associated [Bitnami Helm chart](https://github.com/bitnami/charts/tree/main/bitnami/memcached).
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If you detect any issue in the `docker-compose.yaml` file, feel free to report it or contribute with a fix by following our [Contributing Guidelines](https://github.com/bitnami/containers/blob/main/CONTRIBUTING.md).
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## Contributing
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We'd love for you to contribute to this container. You can request new features by creating an [issue](https://github.com/bitnami/containers/issues) or submitting a [pull request](https://github.com/bitnami/containers/pulls) with your contribution.
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## Issues
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If you encountered a problem running this container, you can file an [issue](https://github.com/bitnami/containers/issues/new/choose). For us to provide better support, be sure to fill the issue template.
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## License
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Copyright © 2025 Broadcom. The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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<http://www.apache.org/licenses/LICENSE-2.0>
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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