I am totally new to Cassandra and met the following error when using cqlsh:
cqlsh
Connection error: Could not connect to localhost:9160
I read the solutions from the following link and tried them all. But none of them works for me.
How to connect Cassandra to localhost using cqlsh?
I am working on CentOS6.5 and installed Cassandra2.0 using yum intall dsc20.
I ran into the same issue running the same OS and same install method. While the cassandra service claims that it's starting ok, if you run service cassandra status it would tell me that the process was dead. Here are the steps I took to fix it:
Viewing the log file at /var/log/cassandra/cassandra.log gave told me that my heap size was too small. Manually set the heap size in /etc/cassandra/conf/cassandra-env.sh:
MAX_HEAP_SIZE="1G"
HEAP_NEWSIZE="256M"
Tips on setting the heap size for your system can be found here
Next, the error log claimed the stack size was too small. Once again in /etc/cassandra/conf/cassandra-env.sh find a line that looks like JVM_OPTS="$JVM_OPTS -Xss128k" and raise that number to JVM_OPTS="$JVM_OPTS -Xss256k"
Lastly, the log complained that the local url was misformed and threw a java exception. I found the answer to the last part here. Basically, you want to manually bind your server's hostname in your /etc/hosts file.
127.0.0.1 localhost localhost.localdomain server1.example.com
Hope this helps~
Change:
/etc/cassandra/cassandra.yaml
Whether to start the thrift rpc server.
start_rpc: false
to
start_rpc: true
Related
When attempting to run Boot inside Docker, using the adzerk/boot-clj image, I receive connection refused errors.
Specifically, when the container starts up, boot is started, and then a stack trace is output. The trace (which is not easy to copy and paste between computers with no connectivity) essentially is to do with downloading - https://github.com/boot-clj/boot/releases/download/2.7.2/boot.jar - and receiving "Connection refused" errors.
I’m asking, and answering this, question in the hope that it might help someone else.
Where to start?
My main problem was with a Docker + Clojure + Boot setup, specifically when running “boot” from inside the container. Doing this spewed out a stack trace. This is where my journey begins.
I’m using the adzerk/boot-clj image. I’ve used it locally (OSX) without issue, the problem I experienced was in using a VM (CentOS 7) hosted within a corporate data center.
docker run -ti adzerk/boot-clj
Issuing this starts up the container, the entry point is Boot, and it starts pulling down some jars, specifically boot.jar from Github. The resulting stack trace details several problems, but the crux of it was
“java.net.ConnectException: Connection refused” (connecting to Clojars.org:443)
Hmmm…
So instead of running Boot straight away in the container, I specified the container entry point as “—-entrypoint bash” so I can prod around a little.
So, wget - connection refused.
What about without Docker in the way. Same thing. Connection refused.
After a little wrangling with the network team, I found that the “https_proxy” env variable needs to be set on CentOS to route traffic out to the internet. A very specific issue to me in the situation.
However….
wget is now fine, both on the host, and inside the adzerk/boot-clj container. Boot however was not.
In an effort to simplify things even more, I took Docker out of the equation entirely, and used boot locally.
Installed java-1.8.0-openjdk.x86_64, installed Boot. Same problem.
So dug around a little, and found this - https ://github.com/boot-clj/boot-bin/issues/2
This was a start. It mentions setting the BOOT_JVM_OPTIONS, specifically https.proxyHost and https.proxyPort.
It still didn’t work… Arrrg.
OK, let’s take Boot out of the equation.
I wrote a test harness in Java, very simple that connects to https ://clojars.org and attempts to read the index page. Copied from https ://docs.oracle.com/javase/tutorial/networking/urls/readingWriting.html, and setting the JVM_OPTS.
It still fails. “Connection refused”
…. Weird beard.
I finally stumbled on this SO - https ://stackoverflow.com/questions/43695299/java-httpurlconnection-works-on-windows-and-fails-on-linux - specifically the answer from Stephen C
“Java doesn't necessarily respect your system's default proxy settings. Since you are able to "curl" the URL on the Linux machine, the most likely explanation is that Java is not using the proxy that you have configured. The following links explains various ways to configure the proxies for Java:”
So taking the first link - https ://stackoverflow.com/questions/120797/how-do-i-set-the-proxy-to-be-used-by-the-jvm - and the answer from Leonel
I issued “java -Dhttps.proxyHost=xxx -Dhttps.proxyPort=80 HelloWorld”
I get an error, but a different one. This is progress. “Unable to tunnel through proxy”
A quick Google of this led me here: http ://www.oracle.com/technetwork/java/javase/8u111-relnotes-3124969.html - “Disable Basic authentication for HTTPS tunneling”
So updated to “java -Dhttps.proxyHost=xxx -Dhttps.proxyPort=80 -Djdk.http.auth.tunneling.disabledSchemes=“” HelloWorld
Profit.
Info:
java -v
openjdk version 1.8.0_144
Openjdk Runtime Environment (build 1.8.0_144-b01)
OpenJDK 64-Bit Server VM (build 25.144-b01, mixed mode)
Sorry for all my profanity Boot.
I am using Neo4j Community Edition 3.1.1 on Mac OS X Sierra. Whenever I try to start Neo4j locally via
neo4j start
I get the following:
Starting Neo4j failed: Component 'org.neo4j.server.database.LifecycleManagingDatabase#a8ba98d' was successfully initialized, but failed to start.
Please see attached cause exception.
with the following exception at the tail of /usr/local/Cellar/neo4j/3.1.1/libexec/logs/neo4j.log
Caused by: org.neo4j.helpers.PortBindException: Address localhost:7687 is already in use, cannot bind to it.
I tried running
lsof -i -n -P | grep 7687
but it came back empty.
Please advise.
Note: I'd leave this as a comment, but don't have the required rep.
Are you sure that you have only one version of Neo4j installed?
Is your installation clean, without any traces of previous installations?
Is your JDK version >= 8?
Have you made other changes to your conf file?
Do you have the desktop app installed? des it work without issues?
Your lsof could be returning an empty value as some pids are only visible to root. Try:
sudo netstat -antlp
This should return all open ports, check if anything corresponds to 7687.
Also try running neo4j as a service. I believe it's launchctl on Mac (I use systemctl on Linux) and check if the error persists.
Cheers
I had the same exact issue, notice how neo4js is trying to get to localhost:7687?
I checked my /etc/hosts file and sure enough, I had a bogus entry for localhost (from previous testing).
I changed /etc/hosts entry back to
localhost 127.0.0.1
Saved, then ran again.
Neo4j started up fine after that.
I have a storm cluster with 1 nimbus node and 3 supervisor node which are running on docker containers on AWS ec2 instances. I had a topology running with the number of workers equal to 3 and it ran perfectly fine. I stopped and removed this container and started a new one. After this, I seem to have the following error in the supervisor logs:
2016-10-03 21:18:22 b.s.m.n.Client [ERROR] connection attempt 129 to Netty-Client-hostname:6702 failed: java.lang.RuntimeException: Returned channel was actually not established
I have edited "/etc/hosts" to include the hostname as follows:
IP-address hostname
Yet, the problems seems to persist. Although, the same topology runs perfectly fine with the number of workers set to 1. Any pointers on solving this issue is appreciated.
The problem was with the hostname. I changed the hostname to match the DNS name by updating "/etc/hostname" as well as "/etc/hosts" and the rebooted nimbus instance followed by the supervisor instances. This fixed the problem. Hope this helps anyone who is stuck with the same problem!
Please check your supervisor log, sometimes you need to redeploy the app because supervisor has not started the topology yet.
I am trying to resolve this network issue which I am facing multiple time while performing any docker commands like "Docker search Ubuntu".
I get an error saying:
"Error response from daemon: server misbehaving.
Can anyone help me on this?
For those who have this problem, it is typically related to having an issue with your DNS being unable to resolve index.docker.io. I had this issue today working from home where my internet connection has a default DNS server that is notoriously flakey.
My dev environment is OSX and I easily solved the issue by changing my DNS servers in network settings to Google's DNS servers (8.8.8.8 and 8.8.4.4) and then restarting my docker host through docker-machine restart MACHINENAME
Faster/Easier Solution: login to docker-machine and fix the dns.
Turns out you don't have to go to all the trouble and waiting associated with restarting docker-machine. Just login to the docker machine (i.e. docker-machine ssh default) and edit /etc/resolv.conf - Add the dns settings from your host machine at the top of resolv.conf.
This is more or less what happens when you restart docker-machine and explains why some repositories are unreachable sometimes after you switch networks.
I also had the exact same problem. Then I stopped the docker-machine and started it--it worked.
Make sure that, when you run this, you are connected to the internet, as Docker needs to be able to do this.
My issue not solved with stated Answer here.
This is problem with resolving Host... I was getting random error time out and misbehave
You need to enable through a configuration property experimentalHostResolver in %APPDATA%\rancher-desktop\settings.json. By default this property is set to false, meaning that the default DNS process in the rancher desktop will be handled through dnsmasq. However, if this property is set to true the default DNS lookup will switch to host-resolver.
NOTE: This feature can only be enabled for Windows currently and it is
an experimental feature
You can take a look at the example settings.json file below as a reference:
"kubernetes":{
"experimentalHostResolver":true <== This is the config!
},
Reference
I'm new to Wildfly and I hope you guys can help me with this problem:
I'm following this tutorial on how to Install Wildfly 8 and when I'm trying to execute step 4 I get the following errors:
I've been googling for a while now and I can't find an answer. I've tryed with JDK 7 and 8, no changes, I'm using admin permissions, I've even tried to download Wildfly again and still no changes.
More experienced co-workers have seen this and don't have a clue about what's going on.
Can you help me? Thanks
The tutorial you linked to, has Wildfly configured to use the default port 8080. Most likely, you have another process or service running which is already using port 8080. Try to find out what process it is and stop it, or try configuring Wildfly to use a different port.
try restart the machine or enable IPV6 in the machine, this error will be resolved
Those having the same problem should check who else uses the port 9990 in your Windows system. TCPView is a good tool to find out the guilty of charge. One of possible common causes in this case is NVIDIA Network Service (NvNetworkService.exe).
If that's the case just find it in your Windows services list and stop/disable it. The service itself is responsible for checking for Nvidia drivers updates, so any time you want it back just turn it on manually.
In my case, I inadvertedly added an AJP socket binding while using standalone jboss_cli utility:
[standalone#localhost:9990 /] /subsystem=undertow/server=default-server/ajp-listener=ajp:add(socket-binding=ajp)
This led to an 'already in use' error that doesn't let any app to start and signaled 503 error through an Apache web server.
I deleted the binding:
/subsystem=undertow/server=default-server/ajp-listener=ajp:remove
And then everything worked normally.
I too had the same issue.After analysis it was found that the SSL port(443 in my case) was creating this issue. I just terminated the processes that were running on 443 and restarted the wildfly and everything worked fine after that.
I had faced same issue with wildfly_8.2.1
Port 8080 was also free, so that solution doesn't worked for me.
Try below procedure as it helped to resolve my issue.
add below lines to your server's /etc/sysctl.conf file
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
No restart is required for this solution.