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> Immutable infrastructure is the future Are there any downsides to immutable infrastructure?

moondev 11y ago
It takes a while to bake the image, and storing thousands of images can add up. However containers can address both points.
dminor 11y ago
Build wait times invoke 90's nostalgia.
phamilton 11y ago
You need to commit to it. You just toe the line. If you currently depend on being able to SSH into boxes and tail logs you will feel a lot of friction. However, practices like those tend to be a crutch anyway.
riskable 11y ago
I'm on a team developing an immutable infrastructure solution with (Docker) containers at a large financial institution. The biggest downsides so far: * It can get complicated very quickly since it involves a lot of stages, systems, and loads of brand new tools where you're unlikely to be able to hire existing talent (you need people who can just read the docs on a complicated tool/architecture like Kubernetes and then start using it). * Speaking of talent, you need developers who are reasonably well-versed in Linux systems administration. Could your developers write a shell script that can configure every little aspect of a Linux host from packaging to authentication? Your developers also need to understand some hard core topics of TCP/IP (e.g. anycast), firewalls (e.g. port mapping), and DNS (TTLs, views, SRV records, and more). They also need to be well-versed in security (e.g. the impact of running as root inside a container) and especially authentication (e.g. HMAC, securely storing shared secrets) and encryption (SSL, managing certificates, knowing which hashing algorithm to use)! * Dealing with existing bureaucracy. Especially rules and policies in regards to security. For example, some people will think that containers and immutable VMs should be treated like regular hosts. That can mean waiting hours for an inventory system to acknowledge their existence before you can put them into production. Or having to wait 30 minutes after every container/VM is brought up so that a security tool can perform a scan even though each container/VM would be identical in every way and have already been scanned before production deployment. Sigh. Of course, a lot of that depends on where you work. At my work right now the biggest challenge is the bureaucracy for certain. If I can get containers classified differently than VMs then all my policy/BAU problems will (likely) go away. If I can't get that then, really, there's no point to our efforts since there would be no advantage to end users (the consumers of what we're building). I may be able to live with a pointless, half-hour-long security scan every time we bring up a new container but I absolutely cannot live with an 8-hour-long wait for a container to show up in our system-of-record (inventory system).
- matt_wulfeck 11y ago
  Sounds like Devops.
- jfindley 11y ago
  We are doing something very similar (mesos rather than k8s), also in a financial organisation. Our main issue is also security - as docker containers aren't very good at actually containing, from a security PoV, we're using SELinux MLS, assigning each container a unique SELinux level/category (fedora-atomic sets this up nicely for you if anyone wants to try). This is great for security, but breaks so many things - lots of the cutting edge work with docker and related tech isn't done by people that care deeply about security, or really understand this sort of usecase, so we run into a huge amount of edgecases and bugs. We spend a lot of time fighting this. It also makes having a really good build/deploy pipeline essential, as well as a good environment set up to reproduce and diagnose issues.
  - je42 11y ago
    Do you have links pointing at what docker containers leak from a security PoV ?
    - riskable 11y ago
      This largely depends on how you're implementing them. If you're using Kubernetes, for example, all Docker containers being managed by Kubernetes can talk to each other without restrictions. From each container's perspective they're part of a big, flat network with no firewalls between them. So if you have a container running the database for client A that means that when client B spins up their little malicious container they can directly connect to client A's DB. That's one way that Docker containers can "leak" (sort of). Another way is that the filesystem for running containers is directly accessible from outside the container. That means that anyone with the power to start/stop containers has the power to read the filesystems for all other containers. There used to be a problem with, "root inside the container is the same as root outside the container" but that was fixed with Docker 1.9 via the new UID mapping feature. So the filesystem and processes running as UID 0 inside the container will actually be some high UID in the parent OS. So unless you're running Red Hat's version of Docker (which is currently hard set to be Docker 1.8!) you can upgrade and solve that problem pretty quickly with a few tweaks.
sytse 11y ago
I think immutable infrastructure still requires a lot of tools and moving parts today. We're spending a lot of time thinking on how to improve this. Two idea's we have: 1. Deploy directly from GitLab to Kubernetes https://gitlab.com/gitlab-org/gitlab-ce/issues/14040 https://gitlab.com/gitlab-org/gitlab-ce/issues/14040 2. Add a container registry to GitLab itself https://gitlab.com/gitlab-org/gitlab-ce/issues/3299 https://gitlab.com/gitlab-org/gitlab-ce/issues/3299 Any comments or suggestions are welcome.

It takes a while to bake the image, and storing thousands of images can add up. However containers can address both points.

dminor 11y ago

Build wait times invoke 90's nostalgia.

phamilton 11y ago

You need to commit to it. You just toe the line. If you currently depend on being able to SSH into boxes and tail logs you will feel a lot of friction. However, practices like those tend to be a crutch anyway.

riskable 11y ago

I'm on a team developing an immutable infrastructure solution with (Docker) containers at a large financial institution. The biggest downsides so far: * It can get complicated very quickly since it involves a lot of stages, systems, and loads of brand new tools where you're unlikely to be able to hire existing talent (you need people who can just read the docs on a complicated tool/architecture like Kubernetes and then start using it). * Speaking of talent, you need developers who are reasonably well-versed in Linux systems administration. Could your developers write a shell script that can configure every little aspect of a Linux host from packaging to authentication? Your developers also need to understand some hard core topics of TCP/IP (e.g. anycast), firewalls (e.g. port mapping), and DNS (TTLs, views, SRV records, and more). They also need to be well-versed in security (e.g. the impact of running as root inside a container) and especially authentication (e.g. HMAC, securely storing shared secrets) and encryption (SSL, managing certificates, knowing which hashing algorithm to use)! * Dealing with existing bureaucracy. Especially rules and policies in regards to security. For example, some people will think that containers and immutable VMs should be treated like regular hosts. That can mean waiting hours for an inventory system to acknowledge their existence before you can put them into production. Or having to wait 30 minutes after every container/VM is brought up so that a security tool can perform a scan even though each container/VM would be identical in every way and have already been scanned before production deployment. Sigh. Of course, a lot of that depends on where you work. At my work right now the biggest challenge is the bureaucracy for certain. If I can get containers classified differently than VMs then all my policy/BAU problems will (likely) go away. If I can't get that then, really, there's no point to our efforts since there would be no advantage to end users (the consumers of what we're building). I may be able to live with a pointless, half-hour-long security scan every time we bring up a new container but I absolutely cannot live with an 8-hour-long wait for a container to show up in our system-of-record (inventory system).

matt_wulfeck 11y ago
Sounds like Devops.
jfindley 11y ago
We are doing something very similar (mesos rather than k8s), also in a financial organisation. Our main issue is also security - as docker containers aren't very good at actually containing, from a security PoV, we're using SELinux MLS, assigning each container a unique SELinux level/category (fedora-atomic sets this up nicely for you if anyone wants to try). This is great for security, but breaks so many things - lots of the cutting edge work with docker and related tech isn't done by people that care deeply about security, or really understand this sort of usecase, so we run into a huge amount of edgecases and bugs. We spend a lot of time fighting this. It also makes having a really good build/deploy pipeline essential, as well as a good environment set up to reproduce and diagnose issues.
- je42 11y ago
  Do you have links pointing at what docker containers leak from a security PoV ?
  - riskable 11y ago
    This largely depends on how you're implementing them. If you're using Kubernetes, for example, all Docker containers being managed by Kubernetes can talk to each other without restrictions. From each container's perspective they're part of a big, flat network with no firewalls between them. So if you have a container running the database for client A that means that when client B spins up their little malicious container they can directly connect to client A's DB. That's one way that Docker containers can "leak" (sort of). Another way is that the filesystem for running containers is directly accessible from outside the container. That means that anyone with the power to start/stop containers has the power to read the filesystems for all other containers. There used to be a problem with, "root inside the container is the same as root outside the container" but that was fixed with Docker 1.9 via the new UID mapping feature. So the filesystem and processes running as UID 0 inside the container will actually be some high UID in the parent OS. So unless you're running Red Hat's version of Docker (which is currently hard set to be Docker 1.8!) you can upgrade and solve that problem pretty quickly with a few tweaks.

sytse 11y ago

I think immutable infrastructure still requires a lot of tools and moving parts today. We're spending a lot of time thinking on how to improve this. Two idea's we have: 1. Deploy directly from GitLab to Kubernetes https://gitlab.com/gitlab-org/gitlab-ce/issues/14040 https://gitlab.com/gitlab-org/gitlab-ce/issues/14040 2. Add a container registry to GitLab itself https://gitlab.com/gitlab-org/gitlab-ce/issues/3299 https://gitlab.com/gitlab-org/gitlab-ce/issues/3299 Any comments or suggestions are welcome.