The Calvin College Emulab Project

Tips and Tidbits

Useful Tips on the Debian router

• In our setup, the Debian router simply needs to perform ip forwarding. To set this up:
  1. Add the line "/net/ipv4/ip_forward=1" to /etc/sysctl.conf
  2. Run the command sysctl -p

• Our Debian box performs an important function in our network having to do with multicast, it runs mrouted. Just use apt-get (apt-get install mrouted) and get it running.

• /etc/init.d/mrouted restart will restart mrouted. You need to do this if frisbee stops working.

Useful Tips on boss

• /usr/testbed/bin/nfree emulab-ops hwdown pc3 will free pc3.

• /usr/testbed/sbin/withadminprivs /usr/testbed/sbin/deletenode pc3 will delete pc3. Sometimes this does not work, and you seem to be chasing your tail like a kitten. Go into the tbdb database and change the EID field in the reserved table to hwdown. Then run the deletenode command as above.

• /usr/testbed/sbin/frisbeelauncher emulab-ops-FBSD410-STD will restart frisbee on boss. You need to do this when a node drops into login mode.

How to terminate an experiment that is not cooperating

Sometimes when you are building your emulab, you get an experiment that cannot be terminated. In this case you need to go into the tbdb database and remove all references to it. Here are some of the tables in which an experiment appears (the field name is always eid). What you actually do is search the database using mysqldumo and grepping the output. Hopefully, you used a distinguishing name for the experiment. Then you remove rows from the listed tables with the criterion being equality with eid.

Mysql tips

Assume that you have typed mysql tbdb

• show tables; will show you all the tables in the database, and there are a lot of them.

• desc table_name; will show you all the fields in the table table_name.

• select * from table_name; will show you all the data in the table table_name.

• select * from table_name where field=value; will display all the data in rows for which field_name has the value value.

• select field_name from table_name; will show you all the data from the field field_name in the table table_name. Separate multiple field names with commas to get a nice tablular output.

• upate table_name set field1=value1 where field2=value2; will change the value of field2 for all rows for which field1 has the value value1.

• upate table_name set field1=value1 where field2=value2; will change the value of field2 for all rows for which field1 has the value value1.

• delete from table_name where field=value; will delete all rows for which field has the value value.