# Waiting for Network Device Interfaces During netlab Provisioning

DevFeed: [Waiting for Network Device Interfaces During netlab Provisioning](<https://devfeed.tech/articles/please-wait-while-we-re-preparing-your-interfaces-11144.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2025/02/wait-for-interfaces/>)

Published: 2025-02-05T06:59:00Z

Content type: article

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [Network](<https://devfeed.tech/topics/network.md>), [virtual machines](<https://devfeed.tech/topics/virtual-machines.md>), [Containers](<https://devfeed.tech/topics/containers.md>), [Vagrant](<https://devfeed.tech/topics/vagrant.md>), [Ansible](<https://devfeed.tech/topics/ansible.md>), [qemu](<https://devfeed.tech/topics/qemu.md>), [ssh](<https://devfeed.tech/topics/ssh.md>)

Tags: [ansible](<https://devfeed.tech/tags/ansible.md>), [cisco](<https://devfeed.tech/tags/cisco.md>), [containers](<https://devfeed.tech/tags/containers.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [network](<https://devfeed.tech/tags/network.md>), [qemu](<https://devfeed.tech/tags/qemu.md>), [ssh](<https://devfeed.tech/tags/ssh.md>), [vagrant](<https://devfeed.tech/tags/vagrant.md>), [virtual-machines](<https://devfeed.tech/tags/virtual-machines.md>)

## AI overview

The article explains why netlab must wait for network device interfaces to become operational after virtual machines and containers start. It describes readiness checks for SSH and interfaces, including differences in Cisco Nexus OS and Junos, and outlines how Ansible profiling is used to measure startup delays.

## Source excerpt

Once a virtual machine running a network operating system boots, you'd expect its data-plane interfaces to be operational, right? Some vendors disagree. It takes over a minute for some network operating systems to figure out they have this thing called interfaces.1 I would love to figure out what takes them so long (a minute is an eternity on modern CPUs), but I guess we'll never know. Behind the Scenes netlab uses two device provisioning mechanisms: it can start virtual machines with Vagrant or containers with containerlab. Some of those containers might use KVM/QEMU to run a hidden virtual machine (see also: RFC 1925 rule 6a). Read more ...