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48 lines
1.2 KiB
Markdown
48 lines
1.2 KiB
Markdown
# Container Super-structure
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- Multiple orchestration platforms support some kind of container super-structure.
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(i.e., a construct or abstraction bigger than a single container.)
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- For instance, on Kubernetes, this super-structure is called a *pod*.
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- A pod is a group of containers (it could be a single container, too).
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- These containers run together, on the same host.
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(A pod cannot straddle multiple hosts.)
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- All the containers in a pod have the same IP address.
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- How does that map to the Docker world?
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---
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class: pic
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## Anatomy of a Pod
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---
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## Pods in Docker
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- The containers inside a pod share the same network namespace.
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(Just like when using `docker run --net=container:<container_id>` with the CLI.)
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- As a result, they can communicate together over `localhost`.
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- In addition to "our" containers, the pod has a special container, the *sandbox*.
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- That container uses a special image: `k8s.gcr.io/pause`.
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(This is visible when listing containers running on a Kubernetes node.)
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- Containers within a pod have independent filesystems.
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- They can share directories by using a mechanism called *volumes.*
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(Which is similar to the concept of volumes in Docker.)
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