Skip to content
Newer
Older
100644 196 lines (155 sloc) 7.47 KB
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 21, 2010
1 ==========
2 Lantorrent
3 ==========
4
5 Lantorrent is a file distribution protocol integrated into the Nimbus
6 IaaS toolkit. It works as a means to multi-cast virtual machine images
7 to many backend nodes. The protocol is optimized for propagating
8 virtual machine images (typically large files) from a central repository
9 across a LAN to many virtual machine monitor nodes.
10
11 Lantorrent works best for the following scenarios:
12
13 1) large file transfers (VM images are typically measured in gigabytes)
14 2) local area switched network (typical for data center computer racks)
15 3) file recipients are willing peers.
16 4) many endpoints request the same file at roughly the same time
17
18 -----------------
19 Protocol overview
20 -----------------
21
22 When an endpoint wants a file it submits a request to a central agent.
23 This agent aggregates request for files so that they can be sent out in
24 an efficient single multi-cast session. Each request for a source file
25 is stored until either N request on that file have been made or N'
26 seconds have passed since the last request on that source file has been
27 made. This allows for a user to request a single file in several
28 unrelated session yet still have the file transfered in an efficient
29 multi-cast session.
30
31 Once N requests for a given source file have been made or N' seconds
32 have passed the destination set for the source file is determined. A
33 chain of destination endpoints is formed such that each node receives
34 from and sends to one other node. The first node receives from the
35 repository and send to a peer node, that peer node sends to another,
36 and so on until all receive the file. In this way all links of the
37 switch are utilized to send directly to another endpoint in the switch.
38 This results in the most efficient transfer on a LAN switched network.
39
40 Often times in a IaaS system a single network endpoint (VMM) will want
41 multiple copies of the same file. Each file is booted as a virtual
42 machine and that virtual machine will make distinct changes to that file
eb04571 @priteau Fix typo in README
priteau authored Mar 4, 2011
43 as it runs, thus it needs its own copy of the file. However that file
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
44 does not need to be transfered across the network more than once.
45 Lantorrent will send the file to each endpoint once and instruct that
46 endpoint to write it to multiple files if needed.
47
48 -----------------------------
49 Enabling Lantorrent in Nimbus
50 -----------------------------
51
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
52 Lan torrent is part of the Nimbus distribution as of Nimbus 2.6.
53 However, due to system administrative overhead it is not enabled by
54 default. To enable Lantorrent in Nimbus there are a few configurations
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
55 changes that must be made.
56
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
57 The following software is required on both service and VMM nodes:
a0c4bcd updating the doc the show a dependency on py 2.5. There is a problem …
BuzzTroll authored Jan 24, 2011
58 - python 2.5
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
59 - python simplejson
eed27d2 @priteau Add a note about dependencies
priteau authored Oct 7, 2010
60
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
61 Lantorrent is run out of xinetd thus it must also be installed on all VMMs.
62
63 To install LANTorrent you must take the following steps:
64
65 1) edit $NIMBUS_HOME/nimbus-setup.conf
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
66 change lantorrent.enabled: False -> lantorrent.enabled: True
67
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
68 2) edit $NIMBUS_HOME/services/etc/nimbus/workspace-service/other/common.conf
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
69 change the value of propagate.extraargs:
70 propagate.extraargs=$NIMBUS_HOME/lantorrent/bin/lt-request
71
72 be sure to expand $NIMBUS_HOME to its full and actual path.
73
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
74 3) install lantorrent on VMM
8d187ea @buzztroll repackaging lantorrent to be more pythonic
buzztroll authored May 19, 2011
75
76 - run: python setup-vmm.py install. This will output the contents of
77 the xinetd configuration file that you will need in the next step.
d3691d5 @priteau Update the LANTorrent installation doc (same info as the admin refere…
priteau authored Jul 12, 2011
78 [optional] You may want to setup a python virtual environment for
79 the installation.
80 To do this, run: virtualenv /path_to_install_lantorrent
81 Then, use the /path_to_install_lantorrent/bin/python binary
82 instead of your system python.
83 [optional] If you don't have Internet connectivity on the VMM, you
84 will have to manually install the simplejson library from source
85 (in the virtual env if you chose to create one).
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
86
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
87 4) install lantorrent into xinetd
8d187ea @buzztroll repackaging lantorrent to be more pythonic
buzztroll authored May 19, 2011
88 - the above step outputs and xinetd file like this:
89
90 ============== START WITH THE NEXT LINE ==================
91 service lantorrent
92 {
93 type = UNLISTED
94 disable = no
95 socket_type = stream
96 protocol = tcp
97 user = bresnaha
98 wait = no
99 port = 2893
100 server = /home/bresnaha/lt1/bin/ltserver
101 }
102 =============== END WITH THE PREVIOUS LINE =================
103
104 note the 'user' value. We strongly recommend that it is not 'root'.
105 This user will be the owner of all received files (the nimbus user)
106
107 Copy the output to a file called /etc/xinetd.d/lantorrent. Once
108 this is done restart xinetd (/etc/init.d/xinetd restart).
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
109
495ba90 lantorrent patches so it will work with older versions of python
BuzzTroll authored Oct 6, 2010
110 5) change the propagation method.
111 - edit the file:
112 $NIMBUS_HOME/services/etc/nimbus/workspace-service/other/authz-callout-ACTIVE.xml
113
114 and change:
115 <property name="repoScheme" value="scp" />
116 to:
117 <property name="repoScheme" value="lantorrent" />
118
aa6a417 @priteau Improve LANTorrent docs, and sync HTML and README
priteau authored Oct 30, 2010
119 6) restart the service: $NIMBUS_HOME/bin/nimbusctl restart
120
121 7) [optional] if the path to Nimbus on the workspace control nodes (VMMs)
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
122 is not /opt/nimbus you will also need to edit a configuration file on
123 all backends.
124
125 In the file:
126 <workspace control path>/control/etc/workspace-control/propagation.conf
127
128 make sure the value of:
129
130 lantorrentexe: /opt/nimbus/bin/ltclient.sh
131
3eb657a @priteau Fix typo
priteau authored Oct 10, 2010
132 points to the proper location of you ltclient.sh script. This should
0b8aa41 merged virga1 and master
BuzzTroll authored Sep 22, 2010
133 be a simple matter of changing /opt/nimbus to the path where you chose
134 to install workspace control.
135
136 ----------------
137 Protocol details
138 ----------------
139
140 requests
141 --------
142
143 transfer
144 --------
145
146 A transfer from one peer to another is performed for forming a TCP
147 connection. A json header is first sent down the socket describing the
148 transfer. It describes the files where data must be written, and the
149 other endpoints where the data must be sent. As data comes in the
150 server will store it to one or more files and forward it on to another
151 endpoint. All of this information is contained in the header. The
152 header has the following format:
153
154 {
155 host
156 port
157 length
158 requests = [ {filename, id, rename}, ]
159 destinations =
160 [ {
161 host
162 port
163 requests = [ { filename, id, rename } ]
164 block_size
165 }, ]
166 }
167
168 When the server forms a connection with the next endpoint it will form
169 another header by removing the first entry of the destination list and
170 using the values contained in it as root level values in the header
171 described above. If the destination list is empty then the server is the
172 last in the chain and no forwarding is needed.
173
174 After the header is sent the binary payload (the contents of the file)
175 is sent down the socket.
176
177 The 'requests' value of the json header contains destination
178 information. Each filename in the list is a file where data should be
179 written. The value of id is the id of the request for that file. The
180 value of rename is a boolean which determines if the file should be
181 first written to a temporary location and then moved to the final
182 location once all of the data is received. This feature is helpful in
183 monitoring file completion.
184
185 security
186 --------
187
188 Each connection to a lantorrent peer comes with a json header. Directly
189 following that header is a line of text in the following format:
190 EOH : <signature>
191
192 The value of signature is the hmac signature of everything that came
193 before the literal EOH. The password for that signature is found in the
194 lt.ini file. Every endpoint and the master repo must have the same
195 value for that password.
Something went wrong with that request. Please try again.