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Release 0.78#

2026-08-08 · Full Changelog

Deploy convergence#

deploy now acts like apply and converges a running lab to the desired state. When the lab is already deployed, containerlab compares the desired topology with the live runtime and applies only the supported delta: add or remove nodes and links, start stopped nodes, and recreate individual nodes when tracked configuration drift is detected.

Repeated deploy calls against an unchanged topology are idempotent. apply is now an alias of deploy; both commands accept the same flags and behave identically. Use --dry-run to preview planned changes and redeploy when you need a full destroy-and-recreate cycle.

In other words, you may find yourself not using deploy --cleanup or deploy -c or redeploy commands anymore, and using deploy instead for lab's lifecycle management.

Thanks @FloSch62 @kaelemc #3274 #3260

Links connected to the nokia_srsim nodes will now default to the new veth-stitch link type when the brief link notation is used. The new veth-stitch link type inserts a transparent tc stitch between two veth segments so traffic can be captured and impaired on links that SR-SIM dataplane interfaces cannot expose directly.

links:
  # this link will use the new `veth-stitch` link type automatically
  # because it is connected to the `nokia_srsim` node
  - endpoints: ["srsim:1/1/c1/1", "srl:e1-1"]

You can still set type: veth-stitch explicitly on any link that needs the same behavior.

Thanks @kaelemc #3270

Topology validation#

The new validate command parses a topology file and runs the schema, node, and link checks as deploy without touching the runtime. Use it locally or in CI to catch topology errors before deployment.

containerlab validate -t mylab.clab.yml

Thanks @kaelemc #3266

Ciena SAOS 10#

The new ciena_saos kind adds support for Ciena SAOS 10.x routers as vrnetlab-backed QEMU VMs.

topology:
  nodes:
    sw1:
      kind: ciena_saos
      image: vrnetlab/ciena_saos:10-12-00-0228
      type: "5164"

Thanks @jgroom33 #3262

PLVision Enterprise SONiC#

The new plvision_sonic kind adds PLVision's Enterprise SONiC Linux Distribution as a vrnetlab-backed VM node. Build a containerlab-compatible image from the vendor qcow2 with vrnetlab and wire dataplane ports as ethN interfaces.

topology:
  nodes:
    sonic1:
      kind: plvision_sonic
      image: vrnetlab/plvision_sonic:lite_1_13_202405

Thanks @romantymoshchuk #3288

Container runtime options#

Topology node definitions can now contain additional container runtime settings for Docker and Podman:

  • privileged — run unprivileged containers when a kind does not require elevated privileges
  • cgroupns-mode — host or private cgroup namespace
  • pid-mode — PID namespace mode, including container:<node> references resolved to lab container names
  • tmpfs — tmpfs mounts keyed by container path
  • security-opts — security options such as seccomp=unconfined
topology:
  nodes:
    svc1:
      kind: linux
      image: alpine:3
      privileged: false
      cgroupns-mode: host
      pid-mode: host
      tmpfs:
        /run: rw,nosuid
      security-opts:
        - seccomp=unconfined

Thanks @orrious #3302

Miscellaneous#

  • SR Linux adds ixr-h6 (7220 IXR-H6) platform support. Thanks @sacckth #3258
  • SR-SIM 26.7+ now accepts ED25519 SSH keys during key injection. Thanks @vista- #3286
  • sonic-vm nodes receive injected SSH keys over scrapligo SSH instead of a bind-mounted authorized_keys file. Thanks @steiler #3269
  • Multi-bind nodes no longer spuriously recreate during deploy/apply reconciliation because bind mount ordering is deterministic. Thanks @FloSch62 #3300
  • Node health and exit wait loops now honor context cancellation. Thanks @mvanhorn #3257
  • Post-install instructions for adding a user to the docker group were clarified. Thanks @skoll43 #3297
  • The structured components syntax that SR-SIM introduced in 0.75 now also works with Nokia SR OS vSIM (nokia_sros). Thanks @kaelemc #3240