9
witchDev
27d

Okay I give up. I just don't get this docker networking stuff. I need someone to save me these sleepless nights and get on a call with me. A docker expert please. I am dying and my make believe devops engineer persona is crashing on me.

Comments
  • 3
    @theKarlisK might want to help 😜
  • 2
    @theKarlisK what do you say ehh?? Have some little time to spare?? Please??? Zoom?? 😁
  • 4
    Here's the ice bucket for docker in general - Docker on CentOS 7 right out the box sorta works, but it needs tweaking and stuff seems to keep breaking despite it. To get it working (specifically networking) you need to disable Firewalld (disable, not remove because it'll throw a hissy-fit and take it's toys with it) and switch to plain iptables. Selinux also keeps getting in the way, even with permissive mode. CentOS8 does not work with Docker - I think RHEL made Podman just so people stopped bugging them about broken Docker on RHEL 7.x and problems with Firewalld. Yes, you can still get Docker installed on CentOS 8 and even get it to work but don't be surprised when it all explodes in your face.

    For best results use something other than Windows, CentOS, RHEL, Fedora or Oracle Linux for running Docker Containers.... or switch to Podman.
  • 2
    @witchDev I can have a quick look here and there via text form messaging (Discord, etc), VoIP is a no go during work hours because it takes away my attention too much and I can't keep working on other issues. I can do a call in like 8h when I'm back home at a PC.
  • 3
    @theKarlisK if you do and can and @witchDev is okay with it please record the call and youtube it as learning resource for others who might be struggling with similar issues
  • 1
    @theKarlisK what of Mac? So I am trying to configure a container to access services hosted on the cloud from within the container(mongo atlas). Mac doesn't have iptables rather, some other shit that I don't understand. I don't have a discord but whatever platform you prefer, I can setup and have a chat when you get to your pc. I am just hell bent on understanding what is going on. I have been able to connect to a bridge network which apparently should allow my container to be seen with the host ip from the outside but for some reason, it is not working out right. Also, this is my first experience with docker so it's really kicking my ass. Any time you can spare, I will take it and appreciate it man.
  • 2
    @witchDev on the other hand, I don't have Zoom. I'll grab a MacBook for tests and throw Docker on it just so I can see for myself. As far as I'm aware there shouldn't be problems with it like on RHEL based distros. I jumped to conclusions about the OS because I had so much problems myself and assumed you'd be using CentOS for server purposes (my mistake).

    In short, in typical situation(say, you haven't created a docker stack or tried specifically setting up it's own network for just this container) Docker Containers live in their own little virtual network, which is bridged to the host system. That way when you create a new container it can reach the outside world but the outside world can't reach back (even with exposed ports). And when you do want to expose a port to the outside world, under typical situation you then get held up by the host systems firewall from everyone on the local network from being able to reach it.
  • 2
    @jester5537 will definitely be writing a post once we crack this. I am sure it would be useful for some other novice experiencing the same issue.
  • 1
    @theKarlisK I haven't tried disabling my firewall but going to try that out now.
  • 1
    @witchDev drop me some details what image you're using. I'm currently omw and once I get home I'll hop to installing latest Docker Desktop for Mac OS X Catalina. Also drop some info what isn't working ... or rather what are you trying to get to work.
  • 1
    @witchDev I'll also see if I can get a crystal ball... err, I mean Zoom set up while I'm prodding the MacOS.
  • 1
    @witchDev you got discord?

    Y'all can set up a docker debug helper discord server and the rest of us can use it too. @theKarlisK
  • 0
    @theKarlisK Okay so context: I am running a scala-play framework app which is connected to a cloud database service (mongo atlas). Reactivemongo is a nice play framework-mongo library that just makes life easier for scala developers. Ideally to connect to any mongo database, all i have to do is configure my mongo uri in my applications conf file. This all works. So moving to containerization, attached is what my dockerfile looks like. Now once i build my image and start the app, it refuses to connect to my mongo cloud service and hits me with No Primary Node error which basically means, my app cannot reach my database. I understand my app from within the container is trying to reach an external service....this is where i am stuck. All my research points dockers networking and i need to be able to connect to services outside my container.
  • 0
    @theKarlisK also my docker-compose here
  • 1
    @NoMad I don't have discord but i can set it up @theKarlisK LOL would that be better than the crystal ball??
  • 3
    @theKarlisK scary realization: turns out my firewall has been off for some time now. (Genuinely terrified coz i don't know how long ago i turned it off..!)
  • 3
    @theKarlisK invite me to the server when you make one 😜

    @witchDev yeah discord is very much easier than zoom.
  • 1
    @witchDev btw, when you make an account, write here the username plus the digits after the # for others to add you.
  • 2
    @NoMad @theKarlisK i setup discord developerAndWitch#9064 We can continue over there.
  • 3
    @witchDev now we have to wait until @theKarlisK gets home... *plays elevator music*
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