When to use Docker-Compose and when to use Docker-Swarm

However, we can use a volume diver to share data across multiple machines. The top-level secrets declaration defines or references
secrets that can be granted to the services in
this stack. The top-level configs declaration defines or references
configs that can be granted to the services in
this stack.

The top-level networks key lets you specify networks to be created. If set to true, specifies that this volume has been created outside of
Compose. Specify which volume driver should be used for this volume. Defaults to whatever
driver the Docker Engine has been configured to use, which in most cases is
local. If the driver is not available, the Engine returns an error when
docker-compose up tries to create the volume. When creating bind mounts, using the long syntax requires the
referenced folder to be created beforehand.

external_links

Instead of just using the default app network, you can specify your own networks with the top-level networks key. This lets you create more complex topologies and specify
custom network drivers and options. You can also use it to connect services to externally-created networks which aren’t managed by Compose. Kubernetes is a portable, open-source, cloud-native infrastructure tool initially designed by Google to manage their clusters.

Docker Machine provides the following command for building an SSH-encrypted connection to the Docker host. We have started with the basics of Docker and docker-compose, and finally, we have compared Docker with the docker-compose, Kubernetes, and docker swarm. We also deployed a voting app using the docker-compose command. Please do let me know if you need more clarification around docker-compose and related terminologies in the comment box.

more stack exchange communities

Additionally, it is not secure or reliable, as you cannot enforce encryption, authentication, or authorization for your service or its communication with other services or networks. Now, if you want these 3 services to be able to run on your cluster of 100’s of machines, and you also want to scale across them, you would need a network that spans multiple hosts. That is where overlay networking (in swarm) comes into picture. Overlay networking is nothing but multi-host networking build over VxLAN technology.

All you wanted to do was learn how to deploy a container to your data center. Fantastic, you have successfully run a production-grade docker swarm application using docker-compose. Let’s proceed further and see the comparison of docker-compose with Kubernetes.

Managing Services

The above example for controlling log files and sizes uses options
specific to the
json-file driver. These particular options are not available on other logging drivers. For a full list of supported logging drivers and their options, refer to the
logging drivers documentation. If your service specifies a
build option, variables defined in
environment files are not automatically visible during the build. Use
the
args sub-option of build to define build-time environment
variables.

• Expose ports without publishing them to the host machine – they’ll only be
  accessible to linked services.
• An image is a compact, executable likeness of an application.
• Docker Swarm offers automatic load balancing, while Kubernetes does not.
• The long form syntax allows the configuration of additional fields that can’t be
  expressed in the short form.
• And you would want the appserver to talk (ping) the db server container and also ping the web server.
• Mount host paths or named volumes, specified as sub-options to a service.

The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. I am unclear if the Docker Swarm deployment stuff actually uses libcompose. In my cursory searches, it would appear that Swarm Mode does not implement libcompose and does its own thing. I am not sure how this relates to the future of Docker Compose and libcompose.

Deploy Docker Compose Services to Swarm

Another variant for external secrets is when the name of the secret in Docker
is different from the name that exists within the service. The following
example modifies the previous one to use the external secret called
redis_secret. You still need to
grant access to the config to each service in the
stack. Another variant for external configs is when the name of the config in Docker
is different from the name that exists within the service.

The Dockerfile in the example makes it possible to create an image of the web application app.py including all requirements (Flask and Redis). A swarm refers to any number Docker engines in swarm mode. Each Docker engine runs on a separate node and integrates it into the cluster. It might take a few minutes to pull all images and start all the containers. Now we have a basic idea about what is Docker containers, let’s proceed further and understand what a dockerfile is. By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Swarm

Swarm Mode has a declarative scaling model where you state the number of replicas you require. The swarm manager takes action to match the actual number of replicas to your request, creating and destroying containers as necessary. As an alternative to cURL, the app can also be accessed via the web browser. Use the local host address or the address of one of the nodes. Thanks to the internal routing network, you can access any node in your swarm on port 8000 to be routed to your app. All images run in the docker-compose.yml file that are locally created and loaded into the registry.

Specify configuration related to the deployment and running of services. The followingsub-options only takes effect when deploying to a swarm with
docker stack deploy, and is
ignored by docker-compose up and docker-compose run, except for resources. In general, docker swarm init is used with the flag –advertise-addr. This indicates which IP address should be used for API access and overlay networking. If the IP address isn’t explicitly defined, Docker automatically checks which IP address the selected system is reachable under and selects this one. If a node has more than one IP address, then the corresponding flag has to be set.

Compose File v3.4 and under

For version 3.3 and below of the format, external cannot be used in
conjunction with other volume configuration keys (driver, driver_opts,
labels). Specify a list of options as key-value pairs to pass to the driver for this
volume. You can mount a host path as part of a definition for a single service, and
there is no need to define it in the top level volumes key. Grant access to secrets on a per-service basis using the per-service secrets
configuration. The
enable_ipv6
option is only available in a
version 2.x Compose file.