Mininet connection problem to ONOS controller - sdn

When I execute the following command
sudo mn --controller remote,ip=127.0.0.1 --topo=single,4
ONOS shows the following Error
Error while processing message from [127.0.0.1:54080
DPID[00:00:00:00:00:00:00:01]]state WAIT_METER_FEATURES_REPLY
io.netty.handler.codec.DecoderExpeption:
org.projectfloodlight.openflow.exeptions.OFParseError: Wrong length:
Expected=40(40), got=32
Kindly Help, How to resolve....?

This is a problem, most likely, related to the OpenFlow version. As #ikerfah said, try to define OpenFlow 1.3 in the mininet command, like:
$ sudo mn --controller=remote,ip=127.0.0.1,port=6653 --switch=ovs,protocols=OpenFlow13 --topo=tree,depth=1,fanout=2

Related

How are the --network options available in podman?

I am running a virtual environment on CentOS with podman.
When I used the --net option of the podman run command, I get an error.
[user#server ~]$ podman run --net slirp4netns:port_handler=slirp4netns -p 1080:80 -d --name web nginx
Error: cannot join CNI networks if running rootless: invalid argument
Is this option unavailable?
Or is there a problem with the way the options are specified?
Please tell me solution.
I used this site as a reference for the command.
This is the configuration of the server.
[user#server ~]$ cat /etc/redhat-release
CentOS Linux release 8.2.2004 (Core)
[user#server ~]$ podman -v
podman version 2.0.6
The port_handler option requires Podman >= 2.1.0, which isn't released at this moment: https://github.com/containers/podman/commit/d86bae2a01cb855d5964a2a3fbdd41afe68d62c8
You can use that option if you compile Podman from its master branch.
I find this link quite helpful to see rootless communication :
https://www.redhat.com/sysadmin/container-networking-podman
https://podman.io/getting-started/network
I am not sure if you have seen this link before or even if it is helpful to you at this instance. But, in view of helping others out, I think the blog post quotes the following helpful statements:
Note: All podman network commands are for rootfull containers only.
Technically, the container itself does not have an IP address, because without root privileges, network device association cannot be achieved
When using Podman as a rootless user, the network is setup automatically. The container itself does not have an IP Address, because without root privileges, network association is not allowed. You will also see some other limitations.

can't start rabbitmq-server after installation

I'm trying to use rabbitmq for a django tutorial but when I want to start the server I get this error:
~$ sudo rabbitmq-server
Configuring logger redirection
14:49:57.041 [error]
14:49:57.044 [error] BOOT FAILED
BOOT FAILED
14:49:57.044 [error] ===========
===========
14:49:57.044 [error] ERROR: could not bind to distribution port 25672, it is in use by another node: rabbit#wss
ERROR: could not bind to distribution port 25672, it is in use by another node: rabbit#wss
14:49:57.045 [error]
14:49:58.046 [error] Supervisor rabbit_prelaunch_sup had child prelaunch started with rabbit_prelaunch:run_prelaunch_first_phase() at undefined exit with reason {dist_port_already_used,25672,"rabbit","wss"} in context start_error
14:49:58.046 [error] CRASH REPORT Process <0.153.0> with 0 neighbours exited with reason: {{shutdown,{failed_to_start_child,prelaunch,{dist_port_already_used,25672,"rabbit","wss"}}},{rabbit_prelaunch_app,start,[normal,[]]}} in application_master:init/4 line 138
{"Kernel pid terminated",application_controller,"{application_start_failure,rabbitmq_prelaunch,{{shutdown,{failed_to_start_child,prelaunch,{dist_port_already_used,25672,\"rabbit\",\"wss\"}}},{rabbit_prelaunch_app,start,[normal,[]]}}}"}
Kernel pid terminated (application_controller) ({application_start_failure,rabbitmq_prelaunch,{{shutdown,{failed_to_start_child,prelaunch,{dist_port_already_used,25672,"rabbit","wss"}}},{rabbit_prelau
Crash dump is being written to: erl_crash.dump...done
I've searched for port to see that if it's in use or not and I used lsof -i :25672 and I get nothing.
I don't know too much about these things so if you need anything please tell me.
Try:
sudo lsof -i :25672
sudo kill <PID>
sudo rabbitmq-server
Where <PID> is the process ID that is occupying port 25672
I have encountered this issue. I figured out that this issue is coming because the rabbitmq-server is already running on the machine.
I have used the following command
rabbitmqctl.bat status to know the status of the rabbitmq-server. This helped me to know if the server is up or down.
If it is up, this could the reason you are getting the error that you have specified in your post.
You can issue the following command to make the server down
rabbitmqctl.bat stop
Now you can try starting the rabbitmq-server by issuing the following command
rabbitmq-server start
Note that I am using Windows. And I have executed these commands by pointing the command prompt to C:\Program Files\RabbitMQ\rabbitmq_server-3.8.14\sbin as my rabbitmq installation directory is C:\Program Files\RabbitMQ\rabbitmq_server-3.8.14.
I have encountered this before. Here is what caused it and how I fixed it:
This is one of those commands which requires the magic word sudo (i.e it needs a superuser privilege).
If you forget to add sudo to the command, it begins the process but later fails when it hits a superuser-only roadblock. This leaves you with an incomplete process. Now when you decide to add sudo, it attempts the same process again but finds out that someone without the right privilege has made a mess or is still messing around.
Then the solution will be to cancel out whatever the first command has started and try again.
sudo lsof -i :25672
This list out details about the port 25672
You will see the PID (process ID) e.g 1301
Then stop the process on that port with:
sudo kill <PID>
for example, sudo kill 1301
And make sure you are killing the right process if not you may get into trouble.
Now, retry the command with sudo:
sudo rabbitmq-server
ALSO,
In most cases, this error occurs because without deliberately stopping the rabbitmq-server, it always keeps running even after you restart you system.
another way to stop rabitmq server windows+R then type "services.msc" and then find for RabitMq.slelect and stop from left top corner.
Then re run your rabitmq server.
-Hi guys, I am putting up an answer that can help Googlers to run multiple rabbitmq-server on the same machine. Trying to achieve the latter, I ran into a similar error reported in the first place and solved that by defining:
export RABBITMQ_DIST_PORT=anything_other_than_25672
as stated in the documentation:
https://www.rabbitmq.com/networking.html#epmd-inet-dist-port-range
if you are using windows go to task manager and stop rabbitmq from running...
then reload the rabbitmq-server
For Linux others answered but in Windows you should press Ctrl+Alt+delete and select task management and in that end proccess that depends on erlang.
Note that it requires Administrator previlage.
Now enter this command to start rabbitmq-server:
rabbitmq-server start
Every time you restart your computer you should do these steps.For prevent do them again you should stop rabbitmq service from startup services.
went through same problem in windows, it is already running after installation as a service
so just enable the plugins from the rabbitmq commandline by entering the code as
rabbitmq-plugins enable management_plugin
than go to the localhost:15672 and good to go.
This means that your port 25672 is already in use
try: -
sudo lsof -i :25672
sudo kill <PID>
and now start your rabbitmq server using
sudo rabbitmq-server

Hyperledger peer creation error

I'm trying to create a genesis block with the command:
peer channel create -c myc
following the install_instantiate.md file.
However I keep getting an error-message that there is no ordering service endpoint created. Somebody who can help me with this please?
I guess you are working with Fabric 1.0.0-alpha. There
the API has been changed so that you have to pass an orderer now.
peer channel create -o orderer0:7050 -c mychannel
Please have a look at the following document:
https://fabric-rtd.readthedocs.io/en/latest/getting_started.html#create-channel
Have you tried to specifiy the orderer address ?
If you are using docker :
CORE_PEER_COMMITTER_LEDGER_ORDERER=orderer:7050 peer channel create -c myc
If it doesn't work, try the Getting Setup, or see the Troubleshooting section

Fail to load ip_conntrack_tftp in iptables

sytemd says:
iptables: Loading additional modules: ip_conntrack_tftp [FAILED]
I didn't find any solutions for Centos7. For Centos prior to 7 it seems to work without problems. lsof etc. doesn't exit for Centos7.
Tftp server works, but there are some problems accessing it through firewalls.
What can I do ?
try
# modprobe ip_conntrack_tftp
and see the logged errors if any
It's solved. the ip_conntrack_tftp module was not compiled for my kernel version.
After doing this, iptables loads without errors.

Unable to connect beagle bone black by ssh

I wanted to install pip onto beagle bone black,and I tried this:
/usr/bin/ntpdate -b -s -u pool.ntp.org
opkg update && opkg install python-pip python-setuptools
then, it threw errors,but Unfortunately, I didn't log that errors.
this is the error:
Collected errors:
* parse_from_stream_nomalloc: Excessively long line at 6. Corrupt file?
it was occurred a week ago and was't solved yet.
I wanted to solve it now and I tried connect by ssh,but I failed.
When I ping to beagle bone, it responds, and Cloud9 IDE is working too but not ssh.
I don't think this is serious problem since I can connect to beagle bone by other methods: Cloud9 or so.
However, to use python on beagle bone, I need to connect by ssh.
Before trying to update and install python-pip, I could connect by ssh.
Do you have any ideas to solve this connection problem?
Reference:
Setting up IO Python Library on BeagleBone Black
View Full Version : [VU+ Duo] Error installing ipk on Vu+ Duo
note
I use default OS: Angstrom
I don't use SD card.
HOST PC is mac, OS.X 10.9
I checked this but this wasn't helpful
Cannot connect to beagle bone black
I could connect by GateOne SSH client, but still unable to connect from terminal.
(Question answered in the comments and in question edits. See Question with no answers, but issue solved in the comments (or extended in chat) )
The OP wrote:
I solved this problem by succeeding update opkg, so I will write the details:
First, remove beaglbone file
rm /var/lib/opkg/lists/beaglebone
and,remove lists folder
rmdir /var/lib/opkg/lists
then, set current time on beagle
/usr/bin/ntpdate -b -s -u pool.ntp.org
afterwards, update and upgrade opkg:
opkg update and opkg upgrade
now you can use opkg !