A little off-topic, but is an availability zone in a separate physical datacenter?
On Sat, Apr 3, 2010 at 5:08 PM, Benjamin Black <b...@b3k.us> wrote: > Right, you determine AZ by looking at the metadata. us-east-1a is a > different AZ from us-east-1b. You can't infer anything beyond that, > either with the AWS API or guesses about IP addressing. My EC2 snitch > recipe builds a config file for the property snitch that treats AZs > like racks (just breaking apart the AZ name, nothing magical), and the > rest is the normal rack aware placement strategy. I am sure folks > _could_ do interesting things on EC2 with extra code, but I don't see > extra code as required for these basic features. > > > b > > On Sat, Apr 3, 2010 at 3:04 PM, Joe Stump <j...@joestump.net> wrote: >> >> On Apr 3, 2010, at 2:54 PM, Benjamin Black wrote: >> >>> I'm pretty familiar with EC2, hence the question. I don't believe any >>> patches are required to do these things. Regardless, as I noted in >>> that ticket, you definitely do NOT need AWS credentials to determine >>> your availability zone. It is available through the metadata web >>> server for each instance as 'placement_availability_zone', avoiding >>> the need to speak the EC2 API or store credentials in the configs. >> >> Good point on the metadata web server. Though I'm unsure how Cassandra would >> know anything about those AZ's without using code that's aware of such >> things, such as the rack-aware strategy we made. >> >> Am I missing something further? I asked a friend on the EC2 networking team >> if you could determine AZ by IP address and he said, "No." >> >> --Joe >> >> > -- Dan Di Spaltro
