I start up an infinispan cache which joins to a cluster. It is the only cache in the cluster.
Now, I connect using JMX to see what ports are being used.
I click on:
CacheManager / MyCache/ CacheManager/ Attributes
Under clusterMembers, I see [mymachine-54202]
Thinking 54202 is the port, I do both a
lsof -i udp
lsof -i tcp
I am on a mac and I can't see anything on 54202. What does 54202 correspond to then?
Thanks
It's a random number to differentiate between multiple caches running on the same box.
For more details, see http://docs.jboss.org/infinispan/5.0/apidocs/config.html#ce_global_transport
Related
I want to create a three node RabbitMQ cluster on a single RHEL8 machine for testing purposes. I tried instructions given in RabbitMQ official guide and also tried to follow this guide.
The first node works fine and it's running. However, the second node cannot be started and throws up an error.
I used below commands as mentioned in the guide.
RABBITMQ_NODE_PORT=5672 RABBITMQ_NODENAME=rabbit rabbitmq-server -detached
RABBITMQ_NODE_PORT=5673 RABBITMQ_NODENAME=hare rabbitmq-server -detached
rabbitmqctl -n hare stop_app
This command throws up below error.
DIAGNOSTICS
attempted to contact: [hare#localhost]
hare#localhost:
connected to epmd (port 4369) on localhost
epmd reports: node 'hare' not running at all
other nodes on localhost: [rabbit]
On further inspection of logs, it seems like that this node tries to use the same ports used by the first node (e.g. MQTT port 1883).
I think I might have to use the other option of declaring /etc/rabbitmq/rabbitmq.conf. Mainly because it seems to give more options to change ports etc.
A sample config file resembling the one needed in my case or a link to a proper guide is highly appreciated.
You didn't specify, but you must have the MQTT plugin enabled for there to be a conflict on that port, correct?
The easiest work-around would be to have two configuration files specifying different ports for MQTT, AMQP and anything else. Then, use the RABBITMQ_CONFIG_FILE environment variable to point to the appropriate file:
RABBITMQ_NODE_PORT=5672 RABBITMQ_NODENAME=rabbit0 \
RABBITMQ_CONFIG_FILE=/path/to/rabbitmq-0.conf rabbitmq-server -detached
RABBITMQ_NODE_PORT=5673 RABBITMQ_NODENAME=rabbit1 \
RABBITMQ_CONFIG_FILE=/path/to/rabbitmq-1.conf rabbitmq-server -detached
NOTE: the RabbitMQ team monitors the rabbitmq-users mailing list and only sometimes answers questions on StackOverflow.
We have an application which uses SSH to copy artifact from one node to other. While creating the Docker image (Linux Centos 8 based), I have installed the Openssh server and client, when I run the image from Docker command and exec into it, I am successfully able to run the SSH command and I also see the port 22 enabled and listening ( $ lsof -i -P -n | grep LISTEN).
But if I start a POD/Container using the same image in the Kubernetes cluster, I do not see port 22 enabled and listening inside the container. Even if I try to start the sshd from inside the k8s container then it gives me below error:
Redirecting to /bin/systemctl start sshd.service Failed to get D-Bus connection: Operation not permitted.
Is there any way to start the K8s container with SSH enabled?
There are three things to consider:
Like David said in his comment:
I'd redesign your system to use a communication system that's easier
to set up, like with HTTP calls between pods.
If you put a service in front of your deployment, it is not going to relay any SSH connections. So you have to point to the pods directly, which might be pretty inconvenient.
In case you have missed that: you need to declare port 22 in your deployment template.
Please let me know if that helped.
i have to create a virtual topology with miniedit that has to talk using the mqtt sub/pub system.
i'm working on virtualbox (mininet-wifi)
i have installed mosquitto & the clients... using the terminals i have no problem with:
mosquitto_sub -t test
mosquitto_pub -t test -m hello!
but when i emulate the topology on Miniedit with (controller,switch and two hosts), the hosts cannot talk using mosquitto, i think that there is no broker that can handle the communications in the virtual topology, any suggestions?
I tried to connect also to a remote server, using cloudmqtt but i only got failed connection
i expect that using
xterm h1 h2
on the Comand Line Interface of miniedit, i would be capable of make the two hosts talks beetween them using
mosquitto_sub/pub system, because also in the xterm of the host, if i type
service mosquitto status
i obtain that
mosquitto is active
UPDATE
solved.
i just have to run another host in which i type "mosquitto" and the others hosts would just reach it using "mosquitto_sub/pub - h 10.0.0.3 for example
2 brokers (1 on each hosts) won't automatically discover each other when the "link" comes up.
You will have to either manually configure the a bridge between the 2 brokers if you want messages to be shared.
Or pick one and have the clients explicitly connect to that one broker. e.g. the -h option for the mosquitto_pub or mosquitto_sub commands.
I agree with the solution. Let me give more in depth explanation.
Run basic mininet topo with 4 hosts and 4 switches.
mn --topo linear,4
Then open xterm for 3 hosts
xterm h1 h2 h3
Three terminals will pop up. One of them will be the host. on h3's(10.0.0.3) xterm terminal run
mosquitto
On h2(10.0.0.2) subscribe to the topic with;
mosquitto_sub -h 10.0.0.3 -t "home/bedroom/light"
On h1(10.0.0.1) publish a message by;
mosquitto_pub -h 10.0.0.3 -t "home/bedroom/light" -m "ON"
You can now see the message on h2's terminal. Hope it helps.
Sorry, should be shot for having to even ask this, but wasted day on this - and feel like I've read everything there is.
I can't create a cluster on my EC2 instances (3) that are spread on three different regions. The hosts:
rabbit#ip-172-31-47-217
rabbit#ip-172-31-1-82
rabbit#ip-172-31-36-111
The initial state before trying to make the cluster:
ubuntu#ip-172-31-47-217:~$ sudo rabbitmqctl cluster_status
Cluster status of node 'rabbit#ip-172-31-47-217' ...
[{nodes,[{disc,['rabbit#ip-172-31-47-217']}]},
{running_nodes,['rabbit#ip-172-31-47-217']},
{partitions,[]}]
ubuntu#ip-172-31-36-111:~$ sudo rabbitmqctl cluster_status
Cluster status of node 'rabbit#ip-172-31-36-111' ...
[{nodes,[{disc,['rabbit#ip-172-31-36-111']}]},
{running_nodes,['rabbit#ip-172-31-36-111']},
{partitions,[]}]
ubuntu#ip-172-31-1-82:~$ sudo rabbitmqctl cluster_status
Cluster status of node 'rabbit#ip-172-31-1-82' ...
[{nodes,[{disc,['rabbit#ip-172-31-1-82']}]},
{running_nodes,['rabbit#ip-172-31-1-82']},
{partitions,[]}]
When I try to check status from one server for another:
sudo rabbitmqctl status -n rabbit#ip-172-31-1-82
Status of node 'rabbit#ip-172-31-1-82' ...
Error: unable to connect to node 'rabbit#ip-172-31-1-82': nodedown
nodes in question: ['rabbit#ip-172-31-1-82']
hosts, their running nodes and ports:
- unable to connect to epmd on ip-172-31-1-82: timeout (timed out)
current node details:
- node name: 'rabbitmqctl3835#ip-172-31-36-111'
- home dir: /var/lib/rabbitmq
- cookie hash: 0tsf/OyQZI7zobmv1Ia97w==
All three servers have the same erlang cookie hash.
I can verify the host names are setup properly:
host ip-172-31-36-111
ip-172-31-36-111.us-west-2.compute.internal has address 172.31.36.111
I know the ports are open:
netstat -plten | grep beam
Because I opened all TCP and UDP at this point as a test, no change.
and finally if this would behave differently given those failures:
sudo rabbitmqctl join_cluster --ram rabbit#ip-172-31-1-82
Clustering node 'rabbit#ip-172-31-47-217' with 'rabbit#ip-172-31-1-82' ...
Error: {cannot_discover_cluster,"The nodes provided are either offline or not running"}
Please help, being driven insane by this.
The problem is that they are in different regions (presumably in EC2-classic - you didn't mention whether you were using a VPC). This means they cannot communicate via their private IPs (see e.g. Can EC2 instances in different regions communicate over their private IP addresses?)
ping 172.31.36.111
will fail from one of the other servers, for example. Pinging using the hostname probably will probably even fail on the DNS lookup.
Your options are:
Put them in separate zones in a single region (in EC2 classic, they will be able to communicate). You could also use a VPC in this case, putting the in separate subnets but allowing interconnections via appropriately set up security groups.
Set up /etc/hosts on each server to point the relevant public IPs of the other servers (you could attach elastic IPs to each server to ensure stability across server restarts). You could also set the hostname of each server for clarity. Set you your security groups to allow access on the relevant ports that rabbitmq uses. There may be security implications of doing this, since the data will be travelling over the public internet.
Set up a VPN between each server in the cluster. Amazon VPC has a VPN facility, but there are ways of setting it up yourself I think.
I think only option 1 is simplest. Option 2 has major security implications (I believe there are ways of securing the connection between the cluster servers, but they aren't documented on the rabbitmq website as far as I can tell). Option 3 is complex but probably the best option if you need multiple regions.
Note that rabbitmq clusters aren't meant to be run over wide geographical areas, since they aren't too reliable in the face of network partitions. See here: https://www.rabbitmq.com/clustering.html
I am having server issues with getting rabbit to cluster.
I boot up two nodes on ec2.
On the the first node booted I do this.
rabbitmqctl stop_app
rabbitmqctl reset
rabbitmqctl start_app
I boot another node.
sudo service rabbitmq-server stop
#Copy cookie from the first server booted
sudo su - -c 'echo -n "cookie" > /var/lib/rabbitmq/.erlang.cookie'
rabbitmqctl stop_app
rabbitmqctl reset
rabbitmqctl cluster rabbit#server1
1) sever1 is running
2) What ports to need open? I have 22, 4369, 5672
sudo rabbitmqctl cluster rabbit#aws-rabbit-server-east-development-20121102162143
Clustering node 'rabbit#aws-rabbit-server-east-development-20121103033005' with ['rabbit#aws-rabbit-server-east-development-20121102162143'] ...
Error: {no_running_cluster_nodes,['rabbit#aws-rabbit-server-east-development-20121102162143'],
['rabbit#aws-rabbit-server-east-development-20121102162143']}
What could possibility be missing from there docs or what what am I missing?
I had a similar problem on EC2 with two windows machines. I eventually got it working but I'm not sure I did it in the correct way so there may be a better solution.
The issue I found was that the two nodes could not see each other when trying to cluster. Each time you start a Rabbit node it seemed to be assigned a port number dynamically.
This obviously makes it very difficult to know which port to open up in the security group so to solve this, I restricted the range of ports Rabbit chose from when assigning the port. I restricted this to a range of 1 port on each node so I always know which port was being assigned.
The easiest way I found to do this was by editing the sbin\rabbitmq-service.bat file.
find the line -kernel inet_default_connect_options "[{nodelay,true}]" ^
add the following two lines to the file underneath:
-kernel inet_dist_listen_min ##### ^
-kernel inet_dist_listen_max ##### ^
replacing ##### with your chosen port number.
So you should now open up the following ports:
5672 - RabbitMQ’s listening port
4369 - Erlang Port Mapper Daemon
##### - the chosen port number for the Erlang nodes to communicate via
Because Erlang does not recognise FQDNs you may need to modify the hosts file on all the servers to make sure they are all able to resolve all the Erlang node name to an IP address, e.g.
123.123.123.111 NODE1
123.123.123.222 NODE2
once this is done you should then be able to see each node from the other. you can do this by using calling the following from the command line (replacing rabbit#NODE2 with whichever node you want to see)
rabbitmqctl status -n rabbit#NODE2
Hope this give you some help, I'm no expert but found this got things working for me!