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Spell check failed with: ``` [kata-spell-check.sh:275] WARNING: Word 'overcommitment': did you mean one of the following?: over commitment, over-commitment, commitment ``` So update this to pass the static checks Fixes: # Signed-off-by: stevenhorsman <steven@uk.ibm.com>
71 lines
2.2 KiB
Markdown
71 lines
2.2 KiB
Markdown
# Kata Containers with `virtio-mem`
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## Introduction
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The basic idea of `virtio-mem` is to provide a flexible, cross-architecture memory hot plug and hot unplug solution that avoids many limitations imposed by existing technologies, architectures, and interfaces.
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More details can be found in https://lkml.org/lkml/2019/12/12/681.
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Kata Containers with `virtio-mem` supports memory resize.
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## Requisites
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Kata Containers just supports `virtio-mem` with QEMU.
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Install and setup Kata Containers as shown [here](../install/README.md).
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### With x86_64
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The `virtio-mem` config of the x86_64 Kata Linux kernel is open.
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Enable `virtio-mem` as follows:
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```
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$ sudo sed -i -e 's/^#enable_virtio_mem.*$/enable_virtio_mem = true/g' /etc/kata-containers/configuration.toml
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```
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### With other architectures
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The `virtio-mem` config of the others Kata Linux kernel is not open.
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You can open `virtio-mem` config as follows:
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```
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CONFIG_VIRTIO_MEM=y
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```
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Then you can build and install the guest kernel image as shown [here](../../tools/packaging/kernel/README.md#build-kata-containers-kernel).
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## Run a Kata Container utilizing `virtio-mem`
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Use following command to enable memory over-commitment of a Linux kernel. Because QEMU `virtio-mem` device need to allocate a lot of memory.
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```
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$ echo 1 | sudo tee /proc/sys/vm/overcommit_memory
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```
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Use following command to start a Kata Container.
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```
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$ pod_yaml=pod.yaml
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$ container_yaml=container.yaml
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$ image="quay.io/prometheus/busybox:latest"
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$ cat << EOF > "${pod_yaml}"
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metadata:
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name: busybox-sandbox1
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uid: $(uuidgen)
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namespace: default
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EOF
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$ cat << EOF > "${container_yaml}"
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metadata:
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name: busybox-killed-vmm
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image:
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image: "$image"
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command:
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- top
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EOF
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$ sudo crictl pull $image
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$ podid=$(sudo crictl runp $pod_yaml)
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$ cid=$(sudo crictl create $podid $container_yaml $pod_yaml)
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$ sudo crictl start $cid
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```
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Use the following command to set the container memory limit to 2g and the memory size of the VM to its default_memory + 2g.
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```
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$ sudo crictl update --memory $((2*1024*1024*1024)) $cid
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```
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Use the following command to set the container memory limit to 1g and the memory size of the VM to its default_memory + 1g.
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```
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$ sudo crictl update --memory $((1*1024*1024*1024)) $cid
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```
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