Containerd client comparison

command

crictl images
nerdctl images --namespace k8s.io

1.nerdctl Whether the same version exists full The difference between

You can start your nerdctl Of release Download the latest executable file from , Each version has two distributions available ：

nerdctl--linux-amd64.tar.gz : Contains only nerdctl.

nerdctl-full--linux-amd64.tar.gz : Contains nerdctl And related dependent components （containerd, runc, CNI, …）.

If you already have it installed Containerd, Just select the previous release , Otherwise, choose the full version .

# tar -zxvf nerdctl-0.21.0-linux-arm64.tar.gz
nerdctl
containerd-rootless-setuptool.sh
containerd-rootless.sh


# tar -zxvf nerdctl-full-0.21.0-linux-arm64.tar.gz
bin/
bin/buildctl
bin/buildg
bin/buildg.sh
bin/buildkitd
bin/bypass4netns
bin/bypass4netnsd
bin/containerd
bin/containerd-fuse-overlayfs-grpc
bin/containerd-rootless-setuptool.sh
bin/containerd-rootless.sh
bin/containerd-shim-runc-v2
bin/containerd-stargz-grpc
bin/ctd-decoder
bin/ctr
bin/ctr-enc
bin/ctr-remote
bin/fuse-overlayfs
bin/ipfs
bin/nerdctl
bin/rootlessctl
bin/rootlesskit
bin/runc
bin/slirp4netns
bin/tini
lib/
lib/systemd/
lib/systemd/system/
lib/systemd/system/buildkit.service
lib/systemd/system/containerd.service
lib/systemd/system/stargz-snapshotter.service
libexec/
libexec/cni/
libexec/cni/bandwidth
libexec/cni/bridge
libexec/cni/dhcp
libexec/cni/firewall
libexec/cni/host-device
libexec/cni/host-local
libexec/cni/ipvlan
libexec/cni/loopback
libexec/cni/macvlan
libexec/cni/portmap
libexec/cni/ptp
libexec/cni/sbr
libexec/cni/static
libexec/cni/tuning
libexec/cni/vlan
libexec/cni/vrf
share/
share/doc/
share/doc/nerdctl/
share/doc/nerdctl/README.md
share/doc/nerdctl/docs/
share/doc/nerdctl/docs/build.md
share/doc/nerdctl/docs/builder-debug.md
share/doc/nerdctl/docs/cni.md
share/doc/nerdctl/docs/compose.md
share/doc/nerdctl/docs/config.md
share/doc/nerdctl/docs/cosign.md
share/doc/nerdctl/docs/dir.md
share/doc/nerdctl/docs/experimental.md
share/doc/nerdctl/docs/faq.md
share/doc/nerdctl/docs/freebsd.md
share/doc/nerdctl/docs/gpu.md
share/doc/nerdctl/docs/ipfs.md
share/doc/nerdctl/docs/multi-platform.md
share/doc/nerdctl/docs/ocicrypt.md
share/doc/nerdctl/docs/registry.md
share/doc/nerdctl/docs/rootless.md
share/doc/nerdctl/docs/stargz.md
share/doc/nerdctl-full/
share/doc/nerdctl-full/README.md
share/doc/nerdctl-full/SHA256SUMS

2. containerd Different clients

ctr

This is containerd Official command line tools , The function is relatively simple , But the basic functions such as pulling images and creating containers all have .

It should be noted that ： ctr Support choice namespace, This namespace No kubernetes Medium namespace, It is containerd Medium namespace, But these two namespace It is similar in concept . One namespace Medium image 、 Containers and other resources , In another namespace You can't see it in .

Operated by default All are default namespace Container and image resources in ,kubernetes Containers in a cluster 、 Images and other resources are placed in k8s.io This namespace in .

We can use -n namespace To specify which namespace, You can also use ctr namespace ls See what namespace. such as , add -n k8s.io Options, you can view kubernetes Container and image resources in .

crictl

crictl yes kubernetes cri-tools Part of , It's for kubernetes Use containerd And specially made , Provides Pod、 Management commands for resources such as containers and images .

It should be noted that ： Use other non kubernetes Created container 、 Mirror image ,crictl It is impossible to see and debug , for instance ctr run In unspecified namespace In this case, the container that runs cannot be used crictl notice . Of course ctr have access to -n k8s.io Specifies the of the operation namespace by k8s.io, So you can see / operation kubernetes Container in cluster 、 Images and other resources . It can be understood as ：crictl The operation specifies containerd Of namespace by k8s.io.

nerdctl

ctr Simple function , And I am used to it docker cli For people who ,ctr Unfriendly （ For example, it can't be like docker cli like that ）. This is the time ,nerdctl Can replace ctr 了 .nerdctl It's a relationship with docker cli Style compatible containerd Of cli Tools , And has been added as a sub project containerd In the project . from nerdctl 0.8 Start ,nerdctl Directly compatible with docker compose The grammar of ( It doesn't contain swarm), This greatly improves the direct integration of containerd As a local development 、 Test and stand-alone container deployment experience .

It should be noted that ： install nerdctl after , If you want to use nerdctl It also needs to be installed CNI Related tools and plug-ins .containerd It does not include the implementation of network functions , Want to implement container networking capabilities such as port mapping , Additional installation required CNI Related tools and plug-ins .

in addition nerdctl You can also use -n Designated to use namespace.

Reference resources

Containers | Containerd A complete introduction