Introduction
Since version 2.3, minimega supports automatic VLAN allocation and aliasing. Previously, users would have to specify and manage VLANs by hand (e.g. DMZ = VLAN 100). Now, minimega assigns VLANs automatically via aliases:
minimega$ vm config net DMZ minimega$ vm config net [DMZ (2)]
Example
Cleanup
$ nuke # /home/ubuntu/launchme.sh new
Boot
# minimega -attach vlans range 150 160 vm config disk /home/ubuntu/tinycore.qcow vm config memory 128 vm config net apples vm launch kvm linux1 vm config net oranges vm launch kvm linux2 vm config net strawberries vm launch kvm linux3 vm start all
Other options
VLANs
Let’s consider the example given in the introduction to this module:
minimega$ vm config net DMZ minimega$ vm config net [DMZ (2)]
In the above example, minimega automatically assigned VLAN 2 to the alias DMZ. You may inspect the current VLAN assignments using the vlans API:
vlans vlans <range,> vlans <range,> <min> <max> vlans <add,> <alias> <vlan> vlans <blacklist,> [vlan]
Let’s unpack the invocation options in this API. With no arguments, vlans prints out the known VLAN aliases and displays information about allocated VLANs:
minimega$ vlans namespace | alias | vlan | DMZ | 2
Here we can clearly see that DMZ is assigned to VLAN 2 in the default namespace. VLAN aliases are namespace-specific. This means that you may reuse the same aliases across experiments and they will be assigned to distinct VLANS:
minimega$ namespace dev minimega[dev]$ vm config net DMZ minimega[dev]$ vlans namespace | alias | vlan dev | DMZ | 3 minimega[dev]$ clear namespace minimega$ vlans namespace | alias | vlan | DMZ | 2 dev | DMZ | 3
As shown above, the vlans API only prints aliases for the current namespace, if one is active.
If users wish to alias VLANs across namespace boundaries, they may use the following syntax:
minimega$ namespace dev2 minimega[dev2]$ vm config net dev//DMZ minimega[dev2]$ vm config net [dev//DMZ (3)]
By default, minimega starts assigning VLANs from VLAN 2. If users wish to restrict the range of VLANs that minimega allocates from, they may do using the vlans range API:
minimega[dev2]$ vlans range 100 200
Now, aliases for dev2 will be restricted to [100, 200). minimega ensures that VLAN ranges for different namespaces do not overlap; conversely, adding a range applies to all new VLAN aliases in the current namespace. Calling vlans range without any arguments will display the user-specified ranges.
Sometimes, experiments require that some aliases map to specific VLANs. To fix the DMZ alias to VLAN 999, use the vlan add API:
minimega[dev2]$ vlan add DMZ 999 minimega[dev2]$ vlan namespace | alias | vlan dev2 | DMZ | 999
VLANs may become blacklisted if users use the directly:
minimega[dev2]$ vm config net 222 2016/03/11 08:18:33 WARN vlans.go:279: Blacklisting manually specified VLAN 222
A blacklisted VLAN will not be used by minimega when assigning a VLAN to a new alias because minimega assumes that the user is doing something special with that VLAN. Users may also use this feature to blacklist VLANs by hand:
minimega[dev2]$ vlan blacklist 333
clear vlans API
The clear vlans API is used to delete aliases. When run with no arguments and a namespace is active, it will clear all the aliases for the namespace. When run with no arguments and no namespace is active, it will clear all state regarding VLAN aliases, including the blacklisted VLANs. When called with an argument, clear vlans will only clear aliases whose prefix matches the supplied argument:
minimega[dev3]$ vlan namespace | alias | vlan dev3 | DMZ | 1000 dev3 | EXTERN_1 | 100 dev3 | EXTERN_2 | 200 dev3 | EXTERN_3 | 300 minimega[dev3]$ clear vlan EXTERN minimega[dev3]$ vlan namespace | alias | vlan dev3 | DMZ | 1000
Other APIs
In the above examples, we showed how VLAN aliases work with the vm config net API. VLAN aliases should be supported everywhere that accepts a VLAN such as tap and vm net.
If you’re unsure of the available aliases, you may try tab completion for any VLAN field.
Tracking VLAN aliases
namespaces assumes that the user issues commands to the head node and that commands may be broadcasted to a cluster of nodes. To prevent total state loss if the head node were to crash, minimega broadcasts VLAN alias assignments. If the alias belongs to a namespace, the assignment in only broadcast to the nodes that are part of the namespace. Otherwise, all nodes receive the update.
Authors
The minimega authors
Created: 30 May 2017
Last updated: 26 April 2022