Minimal Working Example Errors

[mwhittaker]

Hello! I've written a very simple echo server in Python and am trying to replicate the server using crane. I've read through the instructions in the README which led me to read new-run.sh, worker-run.py, worker-build.py, master.py, etc. I couldn't run those scripts out of the box, so I tried to write the simplest script I could to replicate the server without them.

I want to run with three servers (running on 127.0.0.1:7000-7002) and three proxies (running on 127.0.0.1:9000-9002). For simplicity, I want to run all three servers and all three proxies on the same machine with Parrot but without LXC. I have the following two config files, which (I hope) set this up properly:

• local.options
• nodes.local.cfg

I run this command three times to run the three proxies. This command succeeds.

libevent_paxos/target/server.out -n $i -r -m s -c nodes.local.cfg -l ./proxy_logs

Then, I ran this to start the servers:

xtern/scripts/wrap-xtern.sh python server.py 700$i

Unfortunately, this does not work. Running this prints

terminate called after throwing an instance of 'boost::interprocess::interprocess_exception'
  what():  No such file or directory

I read through the code and found that the first second line of code in paxq_open_shared_mem inside of paxos-op-queue.cpp is throwing the exception. It looks like there are some files that it expects to exist inside of /dev/shm that don't exist. Do I have to make some files first before running my server? I noticed the paxq_create_shared_mem function above, but it is never called in the code. I added a call to it myself and then the server runs! But, unfortunately when I try to connect a client to a proxy, the messages are not being delivered.

Long story short, I want to replicate a simple server with crane as simply as possible and am running into some troubles. Any help or guidance would be greatly appreciated!

[hemingcui]

Dear Michael, I suggest you use our evaluation script (the *.py) to set up the Crane instances on different machines and run them. My student Cheng Wang (cc'ed) will help you set them up and answer your question.

…

On Tue, Apr 24, 2018 at 12:11 PM, Michael Whittaker < ***@***.***> wrote: Hello! I've written a very simple echo server <https://github.com/mwhittaker/crane/blob/tweaks/apps/echo/server.py> in Python and am trying to replicate the server using crane. I've read through the instructions in the README which led me to read new-run.sh, worker-run.py, worker-build.py, master.py, etc. I couldn't run those scripts out of the box, so I tried to write the simplest script I could to replicate the server without them. I want to run with three servers (running on 127.0.0.1:7000-7002) and three proxies (running on 127.0.0.1:9000-9002). For simplicity, I want to run all three servers and all three proxies on the same machine with Parrot but without LXC. I have the following two config files, which (I hope) set this up properly: - local.options - nodes.local.cfg I run this command three times to run the three proxies. This command succeeds. libevent_paxos/target/server.out -n $i -r -m s -c nodes.local.cfg -l ./proxy_logs Then, I ran this to start the servers: xtern/scripts/wrap-xtern.sh python server.py 700$i Unfortunately, this does not work. Running this prints terminate called after throwing an instance of 'boost::interprocess::interprocess_exception' what(): No such file or directory I read through the code and found that the first second line of code in paxq_open_shared_mem inside of paxos-op-queue.cpp is throwing the exception. It looks like there are some files that it expects to exist inside of /dev/shm that don't exist. Do I have to make some files first before running my server? I noticed the paxq_create_shared_mem function above, but it is never called in the code. I added a call to it myself and then the server runs! But, unfortunately when I try to connect a client to a proxy, the messages are not being delivered. Long story short, I want to replicate a simple server with crane as simply as possible and am running into some troubles. Any help or guidance would be greatly appreciated! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#13>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AC8Q7OdwQkli6mrfdEOm7_l6y5tqXrEGks5trqXpgaJpZM4Tg-YP> .

[cwang9208]

Hi @mwhittaker, the /dev/shm is used for the timebubble technique in Crane. Specifically, /dev/shm is used for the communication between the proxy and DMT. For your second question, paxq_create_shared_mem will only invoked by proxy when you have specified sched_with_dmt in the configuration file.

In a word, as mentioned by Dr.Heming, we recommend you to use our automatic scripts, otherwise there might be some weird problems that are difficult to debug.

[mwhittaker]

Hi @mwhittaker, the /dev/shm is used for the timebubble technique in Crane. Specifically, /dev/shm is used for the communication between the proxy and DMT. For your second question, paxq_create_shared_mem will only invoked by proxy when you have specified sched_with_dmt in the configuration file.

Ah, I see.

In a word, as mentioned by Dr.Heming, we recommend you to use our automatic scripts, otherwise there might be some weird problems that are difficult to debug.

Okay, I'll give that a shot! Thanks for the quick help @hemingcui and @wangchenghku!

[mwhittaker]

I've set everything up to run on three EC2 servers with user name ubuntu. I'm running the following command:

USER=ubuntu ./new-run.sh configs/echo.sh no_build joint_sched 1

where echo.sh is this file. When worker-run.py is called on one of the servers, it calls this command:

/home/ubuntu/crane/xtern/scripts/wrap-xtern.sh 'python /home/ubuntu/crane/apps/echo/server.py'

which returns the following error message:

terminate called after throwing an instance of 'boost::interprocess::interprocess_exception'
  what():  No such file or directory
/home/ubuntu/crane/xtern/scripts/wrap-xtern.sh: line 6: 27350 Aborted                 (core dumped) python /home/ubuntu/crane/apps/echo/server.py

which is the same one I was experiencing before. @wangchenghku, how should I go about fixing this? You said earlier "paxq_create_shared_mem will only invoked by proxy when you have specified sched_with_dmt in the configuration file", but I do have sch_dmt=1 in my config file, so I think I have that option specified?