The Dockerfile is essentially the instructions for deploying from scratch. Sure, they most likely only exist for one distro but adapting isn’t a huge chore.
You can also clone the repo and build the container yourself. If you want to update say, log4j, and then attempt to build it, that’s still entirely possible and easier than from scratch considering the build environment is consistent.
If I’m updating the source code already I might as well build my service from it, I really don’t see how building a docker container afterward makes it easier considering the update can also break compatibility with the docker environment.
Also adapting can be a pita when the package is built around a really specific environment. Like if I see that the dockerfile installs a MySQL database can I instead connect it to my PostgreSQL database or is it completely not compatible? That’s not really something the dockerfile would tell me.
I really don’t see how building a docker container afterward makes it easier
What it’s supposed to make easier is both sandboxing and reuse / deployment. For example, Docker + Traefik makes some tasks so incredibly easy and secure compared to running them on bare metal. Or if you need to spin up multiple instances, they can be created and destroyed in seconds. Without the container, this just isn’t feasible.
The dockerfile uses MySQL because it works. If you want to know if the core service works with PostgreSQL, that’s not really on the guy who wrote the dockerfile, that’s on the application maintainer. Read the docs, do some testing, create your own container using its own PostgreSQL or connecting to an external database if that suits your needs better.
Once again the flexibility of bind mounts means you could often drop that external database right on top of the one in the container. That’s the real beauty of Docker IMO, being able to slot the containers into your system seamlessly due to the mount system.
adapting can be a pita when the package is built around a really specific environment
That’s the great thing about Docker, it lets you bring that really specific environment anywhere and in an incredibly lightweight manner compared to the old days of heavyweight VMs. I’ve even got Docker containers running on a Raspberry Pi B+ that otherwise is so old that it would be nearly impossible to install the libraries required to run modern software.
The Dockerfile is essentially the instructions for deploying from scratch. Sure, they most likely only exist for one distro but adapting isn’t a huge chore.
You can also clone the repo and build the container yourself. If you want to update say, log4j, and then attempt to build it, that’s still entirely possible and easier than from scratch considering the build environment is consistent.
If I’m updating the source code already I might as well build my service from it, I really don’t see how building a docker container afterward makes it easier considering the update can also break compatibility with the docker environment.
Also adapting can be a pita when the package is built around a really specific environment. Like if I see that the dockerfile installs a MySQL database can I instead connect it to my PostgreSQL database or is it completely not compatible? That’s not really something the dockerfile would tell me.
What it’s supposed to make easier is both sandboxing and reuse / deployment. For example, Docker + Traefik makes some tasks so incredibly easy and secure compared to running them on bare metal. Or if you need to spin up multiple instances, they can be created and destroyed in seconds. Without the container, this just isn’t feasible.
The dockerfile uses MySQL because it works. If you want to know if the core service works with PostgreSQL, that’s not really on the guy who wrote the dockerfile, that’s on the application maintainer. Read the docs, do some testing, create your own container using its own PostgreSQL or connecting to an external database if that suits your needs better.
Once again the flexibility of bind mounts means you could often drop that external database right on top of the one in the container. That’s the real beauty of Docker IMO, being able to slot the containers into your system seamlessly due to the mount system.
That’s the great thing about Docker, it lets you bring that really specific environment anywhere and in an incredibly lightweight manner compared to the old days of heavyweight VMs. I’ve even got Docker containers running on a Raspberry Pi B+ that otherwise is so old that it would be nearly impossible to install the libraries required to run modern software.