This trace follows the actual state transitions behind the companion Containers Package Processes With Shared-Kernel Isolation. It describes a common execution path; implementation details can vary, so keep the contract separate from the mechanism.
Step 1: Select image and entrypoint
A container is a way to package a process and its dependencies while applying isolation and resource controls. On Linux, containers commonly use namespaces to present scoped views of resources and control groups to account for or limit resource consumption. Containers generally share the host kernel.
Step 2: Create isolated namespaces
A container image supplies filesystem layers and runtime configuration. At launch, the container runtime creates a process with selected namespaces, mounts, capabilities, and cgroup limits. The process still uses the host kernel’s system-call interface, which is why kernel compatibility and security policy matter.
Step 3: Apply resource controls
The process sees scoped resources through namespaces and cgroups but still issues system calls to the shared host kernel; the image does not package a private kernel.
At this point, record the state that changed and check the invariant before advancing. If the operation repeats, make clear which values persist and which are recomputed.
Step 4: Run against the host kernel
Containers are not virtual machines with a separate guest kernel by default. A container can escape intended boundaries if host configuration or privileges are unsafe. Resource limits can prevent one process from consuming all memory, but hard limits also cause throttling or termination when set too low.
Step 5: Observe limits and exits
A container works on a developer laptop but fails on a server with an architecture mismatch. Identify what an image does and does not guarantee about the kernel and CPU.
The trace is complete when the result satisfies the stated contract. Compare this model with the concrete runtime or system you are studying before making a performance claim.