Changes between Version 7 and Version 8 of UsersGuide


Ignore:
Timestamp:
Oct 15, 2012 5:37:41 PM (7 years ago)
Author:
Ted Faber
Comment:

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  • UsersGuide

    v7 v8  
    199199Requested a QEMU node with more than 7 experimental interfaces.  Qemu nodes
    200200can only support 7 experimental interfaces.
    201 
    202 
    203 }}}
    204 
    205 The good news is that the container system is using qemu containers to build our experiment.  Unfortunately qemu containers only support 7 experimental interfaces, an internal limit on the number of interfaces the virtual hardware supports.  A
     201}}}
     202
     203The good news is that the container system is using qemu containers to build our experiment.  Unfortunately qemu containers only support 7 experimental interfaces, an internal limit on the number of interfaces the virtual hardware supports.  A [attachment:example2.tcl version of the topology with fewer satellites] will containerize without error.
     204
     205{{{
     206$ /share/containers/containerize.py --default-container qemu DeterTest example2 ~/example2.tcl
     207Containerized experiment DeterTest/example2 successfully created!
     208Access it via http://www.isi.deterlab.net//showexp.php3?pid=DeterTest&eid=example2
     209}}}
     210
     211The qemu experiment looks much like the openvz experiment above, at this small scale.  Qemu nodes more completely emulate hardware and the kernels are independent, unlike openvz containers.  For example, a program can load kernel modules in a qemu VM, which it cannot do in an openvz container.  The qemu containers load the Ubuntu 12.04 (32 bit) distribution by default.
     212
     213We can also swap in the experiment using ViewOS processes, but processes cannot be manipulated from outside.  They are too lightweight to allow an ssh login, though they will run a start command.
     214
     215=== Mixing Containers ===
     216
     217Mixing containers requires the experimenter to assign container types in their topology assignment.  This is done by attaching an attribute to nodes.  The attribute is named {{{containers:node_type}}}.  If the experiment definition is in [http://fedd.isi.deterlab.net/wiki/TopDl topdl] the attribute can be attached using the [http://fedd.deterlab.net/wiki/TopdlLibrary#SharedFunctions standard topdl routines].  Attaching the attribute in ns2 is done using the DETER {{{tb-add-node-attribute}}} command.
     218
     219{{{
     220tb-add-node-attribute $node containers:node_type openvz
     221}}}
     222
     223That command in an ns2 topology description will set {{{node}}} to be placed in an openvz container.  Using this feature, we can modify our [attachment:example1.tcl first topology] to consist of qemu nodes and a single process container in the center.  Process nodes can have unlimited interfaces, but we cannot log into them.  The new topology file looks like this:
     224
     225{{{
     226source tb_compat.tcl
     227set ns [new Simulator]
     228
     229# Create the center node (named by its variable name)
     230set center [$ns node]
     231# The center node is a process
     232tb-add-node-attribute $center containers:node_type process
     233
     234# Connect 10 satellites
     235for { set i 0} { $i < 10 } { incr i} {
     236    # Create node n-1 (tcl n($i) becomes n-$i in the experiment)
     237    set n($i) [$ns node]
     238    # Satellites are qemu nodes
     239    tb-add-node-attribute $n($i) containers:node_type qemu
     240    # Connect center to $n($i)
     241    ns duplex-link $center $n($i) 100Mb 10ms DropTail
     242}
     243
     244# Creation boilerplate
     245$ns rtptoto Static
     246$ns run
     247}}}
     248