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资源说明：["Linux VM", ["Erlang Process", ["Erlang VM"]]].
# Spawn Linux VMs as Erlang processes in the Erlang VM.
evum makes a Linux virtual machine into an Erlang actor. While the Linux
VM has its own state like any other process (memory, system processes,
disk), all I/O with the outside world is sent as messages through the
Erlang VM (currently working: network, system console).
# REQUIREMENTS
sudo apt-get install user-mode-linux
# TODO
* persistent state mounted as filesystem
# EXAMPLE
## Quick Start
* Download and create a buildroot instance
1> {ok, Ref} = evm:create([
{label, test1}, % Label identifying this vm
{dist, buildroot} % Linux distribution image, defined in priv/evm.cfg
]).
{ok,<0.60.0>}
2> flush(). % See the boot messages
3> evum:send(test1, "hostname").
4> flush().
Shell got <<"evm">>
ok
* Download and create an OpenWRT instance with network access
Set the network configuration for your VM in priv/evm.cfg:
{network, [
{home, [
{base_ip, "192.168.213."},
{first_ip, 92},
{netmask, "255.255.255.0"},
{gw, "192.168.213.1"}
]}
]}.
Create the OpenWRT VM:
1> {ok, Ref} = evm:create([
{label, test2}, % Label for this vm
{dist, openwrt}, % Defined in priv/evm.cfg
{net, coffeeshop} % Set up networking: see priv/evm.cfg
]).
{ok,<0.60.0>}
From another host (NOTE: will not work from the system running evum),
telnet to the IP address of the OpenWRT VM:
telnet 192.168.213.92 # or: nc -t 192.168.213.92 22
Run some commands in the VM. All the network data is proxied through
Erlang:
opkg update # may need to adjust /etc/resolv.conf first
opkg install erlang
erl
## Using the Host OS
% Start the network
1> {ok,Switch} = evum_switch:start().
{ok,<0.43.0>}
% Start the system console server
2> evum_ctl:start(Switch).
{ok,<0.58.0>}
% Start a Linux VM
3> {ok,R1} = evum:start().
{ok,<0.61.0>}
% And another VM ...
3> {ok,R2} = evum:start().
4ok,<0.64.0>}
% One more VM ...
5> {ok,R3} = evum:start().
{ok,<0.67.0>}
% See the Linux boot messages
6> flush().
% Set up the network interfaces
7> evum:ifconfig(R1, {"192.168.213.92","255.255.255.0","192.168.213.1"}).
8> evum:ifconfig(R2, {"192.168.213.93","255.255.255.0","192.168.213.1"}).
9> evum:ifconfig(R3, {"192.168.213.94","255.255.255.0","192.168.213.1"}).
10> evum:send(R1, "ifconfig -a").
<<"root@(none):/# ifconfig -a">>
11> flush().
Shell got <<"eth0 Link encap:Ethernet HWaddr 00:21:5d:7c:11:11 ">>
Shell got <<" inet addr:192.168.213.92 Bcast:192.168.213.255 Mask:255.255.255.0">>
Shell got <<" UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1">>
Shell got <<" RX packets:0 errors:0 dropped:0 overruns:0 frame:0">>
Shell got <<" TX packets:0 errors:0 dropped:0 overruns:0 carrier:0">>
Shell got <<" collisions:0 txqueuelen:1000 ">>
Shell got <<" RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)">>
Shell got <<" Interrupt:5 ">>
Shell got <<>>
Shell got <<"lo Link encap:Local Loopback ">>
Shell got <<" LOOPBACK MTU:16436 Metric:1">>
Shell got <<" RX packets:0 errors:0 dropped:0 overruns:0 frame:0">>
Shell got <<" TX packets:0 errors:0 dropped:0 overruns:0 carrier:0">>
Shell got <<" collisions:0 txqueuelen:0 ">>
Shell got <<" RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)">>
Shell got <<>>
% Ping something, so our fake switch can learn of the VM's prescence
12> evum:ping(R1, {192,168,213,7}).
13> evum:ping(R2, {192,168,213,7}).
14> evum:ping(R3, {192,168,213,7}).
8> flush().
Shell got <<"PING 192.168.213.7 (192.168.213.7) 56(84) bytes of data.">>
Shell got <<"64 bytes from 192.168.213.7: icmp_seq=1 ttl=64 time=53.9 ms">>
Shell got <<>>
Shell got <<"--- 192.168.213.7 ping statistics ---">>
Shell got <<"1 packets transmitted, 1 received, 0% packet loss, time 0ms">>
Shell got <<"rtt min/avg/max/mdev = 53.918/53.918/53.918/0.000 ms">>
% start up a shell (of sorts) on a port
10> evum:send(R, "socat tcp-l:7777,reuseaddr,fork system:'/bin/bash',stderr &").
<<"root@(none):/# socat tcp-l:7777,reuseaddr,fork system:'/bin/bash',stderr &">>
From another host:
$ nc 192.168.213.92 7777
cat /proc/cpuinfo
processor : 0
vendor_id : User Mode Linux
model name : UML
mode : skas
host : Linux rst 2.6.32-26-generic #48-Ubuntu SMP Wed Nov 24 09:00:03 UTC 2010 i686
bogomips : 1468.00
# SCREENSHOT: Erlang in Erlang!
root@OpenWrt:/tmp# opkg install erlang
Installing erlang (R13A-1) to root...
Downloading http://downloads.openwrt.org/backfire/10.03/x86/packages/erlang_R13A-1_x86.ipk.
Installing libncurses (5.7-2) to root...
Downloading http://downloads.openwrt.org/backfire/10.03/x86/packages/libncurses_5.7-2_x86.ipk.
Installing librt (0.9.30.1-42) to root...
Downloading http://downloads.openwrt.org/backfire/10.03/x86/packages/librt_0.9.30.1-42_x86.ipk.
Configuring libncurses.
Configuring librt.
Configuring erlang.
root@OpenWrt:/tmp# erl
Erlang R13A (erts-5.7) [source] [rq:1] [kernel-poll:false]
Eshell V5.7 (abort with ^G)
1> spawn(io, format, ["Erlang process spawned in an Erlang VM in a Linux VM in an Erlang process in an Erlang VM~n"]).
Erlang process spawned in an Erlang VM in a Linux VM in an Erlang process in an Erlang VM
<0.35.0>
2>
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