Cluster Management in VisLab/Archive - Revision history

Giovanni Saponaro: /* Forcing uname to give the desired output */ monospace

2009-09-10T11:06:05Z

Forcing uname to give the desired output: monospace

← Older revision		Revision as of 11:06, 10 September 2009
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	(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?", that is, on which server it is running.		(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?", that is, on which server it is running.

	== Forcing uname to give the desired output ==		== Forcing <code>uname</code> to give the desired output ==

	Since we want each machine of the cluster to provide its unique name (i.e., cortex1 ... cortex5) as the output of "uname -n", we can use the following command to do the job:		Since we want each machine of the cluster to provide its unique name (i.e., cortex1 ... cortex5) as the output of "uname -n", we can use the following command to do the job:

Giovanni Saponaro at 11:39, 13 May 2009

2009-05-13T11:39:29Z

← Older revision		Revision as of 11:39, 13 May 2009
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	Some obsolete information about [[Cluster Management in VisLab]] is kept here, for the sake of history.		Some obsolete information about [[Cluster Management in VisLab]] is kept here, for the sake of history.

	= Cortex and the uname command =		== Cortex and the uname command ==

	Prior to 2009-05-12, the command		Prior to 2009-05-12, the command

Giovanni Saponaro: create index

2009-05-13T11:37:40Z

create index

← Older revision		Revision as of 11:37, 13 May 2009
Line 1:		Line 1:
	Some obsolete information about [[Cluster Management in VisLab]] is kept here, for the sake of history.		Some obsolete information about [[Cluster Management in VisLab]] is kept here, for the sake of history.

	== Cortex and the uname command ==		= Cortex and the uname command =

	Prior to 2009-05-12, the command		Prior to 2009-05-12, the command
Line 7:		Line 7:
	(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?", that is, on which server it is running.		(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?", that is, on which server it is running.

	=== Forcing uname to give the desired output ===		== Forcing uname to give the desired output ==

	Since we want each machine of the cluster to provide its unique name (i.e., cortex1 ... cortex5) as the output of "uname -n", we can use the following command to do the job:		Since we want each machine of the cluster to provide its unique name (i.e., cortex1 ... cortex5) as the output of "uname -n", we can use the following command to do the job:
Line 24:		Line 24:
	* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n".		* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n".

	=== Old workaround ===		== Old workaround ==

	Before 2009-05-12 we were customizing $ICUB_DIR/scripts/yarprun.sh and saving our own version as yarprunVislab.sh. Since "uname -n" outputted "source" on all of the 5 Cortex computers, we changed the line		Before 2009-05-12 we were customizing $ICUB_DIR/scripts/yarprun.sh and saving our own version as yarprunVislab.sh. Since "uname -n" outputted "source" on all of the 5 Cortex computers, we changed the line

Giovanni Saponaro: /* Forcing uname to give the desired output */ bold -> italics

2009-05-13T11:36:40Z

Forcing uname to give the desired output: bold -> italics

← Older revision		Revision as of 11:36, 13 May 2009
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	The shopt line makes aliases valid in non-interactive shells. The second line, containing the actual "uname" alias, contains three commands separated by semicolons:		The shopt line makes aliases valid in non-interactive shells. The second line, containing the actual "uname" alias, contains three commands separated by semicolons:
	* "echo -n cortex" prints the word "cortex" '''without''' a trailing newline;		* "echo -n cortex" prints the word "cortex" ''without'' a trailing newline;
	* "ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'" extracts the last byte of the current machine's IP address;		* "ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'" extracts the last byte of the current machine's IP address;
	* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n".		* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n".

Giovanni Saponaro: /* Cortex and the uname command */ fix writing

2009-05-13T11:23:54Z

Cortex and the uname command: fix writing

Giovanni Saponaro: add link to main article

2009-05-12T16:28:38Z

add link to main article

← Older revision		Revision as of 16:28, 12 May 2009
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	Some obsolete information is kept here, for the sake of history.		Some obsolete information about [[Cluster Management in VisLab]] is kept here, for the sake of history.

	== Cortex and the uname command ==		== Cortex and the uname command ==

Giovanni Saponaro: /* Forcing uname to give the desired output */ further explanation of alias

2009-05-12T16:11:30Z

Forcing uname to give the desired output: further explanation of alias

← Older revision		Revision as of 16:11, 12 May 2009
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	The idea is to enforce that custom command as a system-wide behaviour in the cluster, by setting an alias called "uname -n" (to be more accurate, the alias is just called "uname", with every additional parameter to be ignored).		The idea is to enforce that custom command as a system-wide behaviour in the cluster, by setting an alias called "uname -n" (to be more accurate, the alias is just called "uname", with every additional parameter to be ignored).

	~~In bash scripting syntax, dollar signs have to be escaped, so~~ the ~~final alias is~~		We added the following lines in user icub's ~/.bashrc:
			shopt -s expand_aliases
	alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"		alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"
	~~We added~~ this in
	* /~~etc~~/~~bash.bashrc (it sets the alias correctly on interactive shells. For it to take effect in non-interactive sessions~~, ~~we also added the line~~ "~~shopt~~ -~~s expand_aliases~~")		The shopt line makes aliases valid in non-interactive shells. The uname alias means this:
			* "echo -n cortex;" prints the word cortex without newline
			* "ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'" extracts the last byte of the current machine IP address;
			* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n"

	=== Old workaround ===		=== Old workaround ===

Giovanni Saponaro: /* Forcing uname to give the desired output */ shopt -s expand_aliases

2009-05-12T15:37:38Z

Forcing uname to give the desired output: shopt -s expand_aliases

← Older revision		Revision as of 15:37, 12 May 2009
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	alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"		alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"
	We added this in		We added this in
	* /etc/bash.bashrc (it sets the alias correctly on interactive shells~~, we need~~ to ~~check~~ non-interactive sessions)		* /etc/bash.bashrc (it sets the alias correctly on interactive shells. For it to take effect in non-interactive sessions, we also added the line "shopt -s expand_aliases")

	=== Old workaround ===		=== Old workaround ===

Giovanni Saponaro: /* Forcing uname to give the desired output */ add "cortex" part to output

2009-05-12T14:57:34Z

Forcing uname to give the desired output: add "cortex" part to output

← Older revision		Revision as of 14:57, 12 May 2009
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	In bash scripting syntax, dollar signs have to be escaped, so the final alias is		In bash scripting syntax, dollar signs have to be escaped, so the final alias is
	alias uname="ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"		alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"
	We added this in		We added this in
	* /etc/bash.bashrc (it sets the alias correctly on interactive shells, we need to check non-interactive sessions)		* /etc/bash.bashrc (it sets the alias correctly on interactive shells, we need to check non-interactive sessions)

Giovanni Saponaro: add old workaround (yarprunVislab.sh)

2009-05-12T14:20:03Z

add old workaround (yarprunVislab.sh)

← Older revision		Revision as of 14:20, 12 May 2009
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	We added this in		We added this in
	* /etc/bash.bashrc (it sets the alias correctly on interactive shells, we need to check non-interactive sessions)		* /etc/bash.bashrc (it sets the alias correctly on interactive shells, we need to check non-interactive sessions)

			=== Old workaround ===

			Before 2009-05-12 we were customizing $ICUB_DIR/scripts/yarprun.sh and saving our own version as yarprunVislab.sh. Since "uname -n" outputted "source" on all of the 5 Cortex computers, we changed the line
			ID=/`uname -n`
			to:
			ID=/`uname -n`
			if [ $ID == "/source" ];
			then
			ID=/cortex` ifconfig eth0 \| grep "inet addr" \| awk '{print $2}' \| awk -F: '{print $2}' \| awk -F. '{print $4}'`;
			fi;
			of course, we had to make a copy of $ICUB_DIR/scripts/icub-cluster.py to $ICUB_DIR/scripts/icub-clusterVislab.py and change all the invocation of yarprun.sh to yarprunVislab.sh in the latter.

			Besides, we had to copy the yarprunVislab.sh on all of the machines (Chico2, pc104). To copy it to pc104, we actually had to copy it to icubsrv, in the correct location (see [[pc104]]):
			scp yarprunVislab.sh 10.10.1.51:/exports/code-pc104/iCub/scripts/

			This method, while cumbersome, was working: from Chico2 we could control "yarp run" on Chico2, pc104, Cortex1..5. We didn't bother to have it running on Cortex6 nor icubsrv, as those computers are very rarely used.

← Older revision		Revision as of 11:23, 13 May 2009
Line 5:		Line 5:
	Prior to 2009-05-12, the command		Prior to 2009-05-12, the command
	uname -n		uname -n
	(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?".		(which normally outputs the unique, alphabetic name of the current machine you are logged in) was not working as we wanted on Cortex. This happened because all the machines in the cluster share the same network disk. In particular, the file /etc/hostname is also shared among all of them; it contains the string "source", which is the real result of "/bin/uname -n" but it is of little information for our "yarp run" script, which sometimes needs to answer the question "where am I?", that is, on which server it is running.

	=== Forcing uname to give the desired output ===		=== Forcing uname to give the desired output ===

	Since we want each machine of the cluster to provide its unique name (i.e., ~~cortex[1~~..5]) as the output of "uname -n", we can use the following command to do the job:		Since we want each machine of the cluster to provide its unique name (i.e., cortex1 ... cortex5) as the output of "uname -n", we can use the following command to do the job:
	ifconfig eth0 \| grep "inet addr" \| awk '{print $2}' \| awk -F: '{print $2}' \| awk -F. '{print $4}'		ifconfig eth0 \| grep "inet addr" \| awk '{print $2}' \| awk -F: '{print $2}' \| awk -F. '{print $4}'
	Basically, this command extracts the last byte from the current machine IP address. For example, if you type it on cortex3 you will get "3" (the last byte of 10.10.1.3) as output.		Basically, this command extracts the last byte from the current machine IP address (the number after the last dot). For example, if you type the command on cortex3 you will get "3" (the last byte of 10.10.1.3) as output.

	The idea is to ~~enforce that~~ custom command as a system-wide behaviour in the cluster, by setting an alias called "uname -n" (to be more accurate, the alias is just called "uname", with every additional parameter to be ignored).		The idea is to make this custom command available as a system-wide behaviour in the cluster, by setting it as an alias called "uname -n" (to be more accurate, the alias is just called "uname", with every additional parameter to be ignored). Note that, by using this trick, we overwrite the output of the real uname command on the machine (should you need it, you can still call it with "/bin/uname").

	We added the following lines in user icub's ~/.bashrc:		To enforce the alias for everyone, we added the following lines in user icub's ~/.bashrc:
	shopt -s expand_aliases		shopt -s expand_aliases
	alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"		alias uname="echo -n cortex; ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'; echo > /dev/null"

	The shopt line makes aliases valid in non-interactive shells. The uname alias ~~means this~~:		The shopt line makes aliases valid in non-interactive shells. The second line, containing the actual "uname" alias, contains three commands separated by semicolons:
	* "echo -n cortex;" prints the word cortex without newline		* "echo -n cortex" prints the word "cortex" '''without''' a trailing newline;
	* "ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'" extracts the last byte of the current machine IP address;		* "ifconfig eth0 \| grep 'inet addr' \| awk '{print \$2}' \| awk -F: '{print \$2}' \| awk -F. '{print \$4}'" extracts the last byte of the current machine's IP address;
	* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n"		* "echo > /dev/null" ignores everything that is typed after "uname", such as "-n".

	=== Old workaround ===		=== Old workaround ===
Line 39:		Line 39:
	scp yarprunVislab.sh 10.10.1.51:/exports/code-pc104/iCub/scripts/		scp yarprunVislab.sh 10.10.1.51:/exports/code-pc104/iCub/scripts/

	This method, while cumbersome, was working: from Chico2 we could control "yarp run" on Chico2, pc104, Cortex1..5. We ~~didn't~~ bother to have it running on Cortex6 ~~nor~~ icubsrv, as those computers are very rarely used.		This method, while cumbersome, was working: from Chico2 we could control "yarp run" on Chico2, pc104, Cortex1..5. We did not bother to have it running on Cortex6 or icubsrv, though, as those computers are very rarely used in demos.