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Find veth pairs on the host which are not in any running containers
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| #!/usr/bin/env bash | |
| # Create associative arrays | |
| declare -A interior=() | |
| declare -A exterior=() | |
| # Make sure ethtool is installed on this host | |
| apt-get install -y ethtool &>/dev/null | |
| # For each container | |
| for container in $(lxc-ls) | |
| do | |
| # For each list of ifindex:ifname pairs, sorted by ifindex, skipping loopback (lo) | |
| for items in $(awk -F': ' '{print $1 ":" $2}' < <(lxc-attach -n $container -- ip -o l | sort -n | tail -n+2)) | |
| do | |
| # For each ifindex:ifname pairs | |
| for item in "${items[@]}" | |
| do | |
| # Split into ifindex and ifname | |
| index=$(echo $item | awk -F':' '{print $1}') | |
| name=$(echo $item | awk -F':' '{print $2}') | |
| # Add entry keyed on ifindex => ifname and container name | |
| interior+=([$index]="$name $container") | |
| done | |
| done | |
| done | |
| # For each ifindex:ifname pair where ifname contains 'veth' | |
| for item in $(ip -o l | grep veth | awk -F': ' '{print $1 ":" $2}') | |
| do | |
| # Split into ifindex and ifname | |
| index=$(echo $item | awk -F':' '{print $1}') | |
| name=$(echo $item | awk -F':' '{print $2}') | |
| # Extract peer ifindex from ethtool | |
| peer=$(ethtool -S $name | awk '/peer_ifindex/ {print $2}') | |
| # Add entry keyed on interior peer's ifindex => ifname | |
| exterior+=([$peer]=$name) | |
| done | |
| # For each peer (interior) ifindex | |
| for peer in "${!exterior[@]}" | |
| do | |
| # Store exterior ifname for this veth pair | |
| extname=${exterior[$peer]} | |
| # If this peer ifindex was also found inside the container | |
| if [[ -n ${interior[$peer]} ]] | |
| then | |
| # Split out values into ifname and container name | |
| items=(${interior[$peer]}) | |
| name="${items[0]}" | |
| container="${items[1]}" | |
| echo "Found peer for interface $extname => $peer:$name in $container" | |
| # Otherwise the exterior veth is dangling; delete it! | |
| else | |
| # This section redirects to stderr only | |
| # You can filter just for this output with: $script 1>/dev/null | |
| echo "Peer $peer for interface $extname not in a container!" >&2 | |
| fi | |
| done |
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