I'm implementing one-way (server to client) replication with SymmetricDS and I'm a bit confused about the configuration to apply to the client node. Should I install SymmetricDS and start the service on the destination server/node?
The servers are CentOS + Oracle 12c database
Yes, you should install a SymmetricDs in server mode at the source node and another SymmetricDs in client mode at the destination node. The server node shouldn't be having a registration URL as it is the source of configuration
yes, you have to install it. Both server and client have their own properties files, by which the SymmetricDS will configure the server and the client. After installing, start the service. Go to your installation folder and check
bin/sym_service install
bin/sym_service start
bin/sym_service status
Related
I have postgreSQL installed on both Windows and Linux Ubuntu VMs.
(1) Is SSL connection possible for PostgreSQL with basic authentication (Username/password authentication) ?
If possible , should the certificates be installed on the client machine , which invokes PostgreSQL
(2) Is pg_hba.conf file present on the PostgreSQL server or client machine ?
Please help
SSL Connection is possible with basic authentication..it is called MD5 authentication.. in Postgres.conf, we have to set ssl=on and in pg_hba.conf we should use hostssl Instead of host...we can also use client certificate option
pg_hba.conf file is present on server where Postgres is installed
We are facing the issue while starting the informatica cluster service.
When starting Informatica cluster services, some scripts installing Ambari server on infabde, bdemaster and bdeslave.
The script is trying to install ambari on infabde again and again in loop, So the cluster service failed to start by saying that Ambari already installed in infabde. Its not trying to install to other two nodes.
Error Log:
2017-01-12 17:10:30,763 [localhost-startStop-1] INFO com.infa.products.ihs.service.ambari.ScriptLauncher- Waiting for Script's streams to end.
2017-01-12 17:10:41,210 [localhost-startStop-1] ERROR com.infa.products.ihs.beans.application.ClusterListener- [InfaHadoopServiceException_00047] The launch of Ambari server on host [infabde.lucidtechsol.com] failed because the host already has an installed Ambari server. You can add the host to another cluster.
com.infa.products.ihs.service.exception.InfaHadoopServiceException: [InfaHadoopServiceException_00047] The launch of Ambari server on host [infabde.hostname.com] failed because the host already has an installed Ambari server. You can add the host to another cluster.
Run the reset script
./ResetScript.sh true user#server.com user#server.com
./ResetScript.sh false user#server.com user#client.com
and enable IHS then.
ResetScript.sh can be found in services/Infahadoopserveice/binaries
I've setup opscenter on one of cassandra cluster nodes. After installation, when setting up my cluster, I tried installation of datastax agent on all the cluster nodes via UI, but it failed. So, I had to install the agents manually.
After manually installing the agents, the node in which opscenter is installed is able to connect, but not the other nodes. It still says, "2 agents failed to connect". What could be the issue?
PS : My cassandra cluster is setup on AWS in ubuntu
My agent.log file looks like this
ERROR [os-metrics-9] 2015-07-27 07:04:43,390 Long os-stats collector failed: Cannot run program "iostat": error=2, No such file or directory
ERROR [os-metrics-7] 2015-07-27 07:04:43,391 Long os-stats collector failed: Cannot run program "iostat": error=2, No such file or directory
ERROR [os-metrics-8] 2015-07-27 07:04:53,391 Long os-stats collector failed: Cannot run program "iostat": error=2, No such file or directory
ERROR [os-metrics-3] 2015-07-27 07:04:53,392 Long os-stats collector failed: Cannot run program "iostat": error=2, No such file or directory
ERROR [StompConnection receiver] 2015-07-27 07:05:02,946 failed connecting to **.**.**.**:61620:java.net.ConnectException: Connection timed out
You have to set the stomp_interface in the address.yaml like
stomp_interface: <ip-address>
After agent restart it should be connected.
As your agent have been able to connect from the same box where opscenter is installed, so it sounds like :
You might have not configured your firewall properly. If you please try by disabling firewall on all your boxes.
You may have multiple interfaces and C* installation picked up an undesired interface. So run ifconfig or ip command on all of your instances and check with C* yaml.
About iostat failure message : You have not install sysstat pkg. Seems, you have not install dependencies as part of DSE install.
The agents uses iostat to collect some information from disks. If it cant find it you will get that error but it just means those metrics will be missing some os metrics (likely a lot of disk and cpu metrics will be missing)
These are some useful configurations that you should keep in mind when starting the agent manually in the conf/address.yaml file:
###A name for the node to use as a label throughout OpsCenter.
alias:
###Reachable IP address of the opscenterd machine. The connection made will be on stomp_port. Internal IP in this case
stomp_interface:
###Port for the agent's HTTP service (default: 61621).
#api_port: 61621
###The stomp_port used by opscenterd. == Must match with the 'incoming_port' in opscenter.conf
stomp_port: 61620
###The IP used to identify the node.
local_interface: 100.73.158.44
###The IP that the agent HTTP server listens on.
agent_rpc_interface:
###Host used to connect to local JMX server.
jmx_host: 100.73.158.44
###Whether or not to use SSL communication between the agent and opscenterd.
use_ssl: 1
To solve the "Cannot run program 'iostat'" error, do this:
sudo apt-get install sysstat
I'm trying to install the enterprise edition of neo4j on an existing EC2 (Amazon linux) instance. So far I've
wget "link to enterprise"
untar the file
renamed and moved the folder to NEO4J_HOME
then went into the config files for neo4j.properties to make the following changes:
# Enable shell server so that remote clients can connect via Neo4j shell.
remote_shell_enabled=true
# The network interface IP the shell will listen on (use 0.0.0 for all interfaces)
remote_shell_host=127.0.0.1
# The port the shell will listen on, default is 1337
remote_shell_port=1337
EDITED Christophe Willemsen pointed out that for my original error, I had forgotten to restart the server at that point but I was still unable to access the web server while it was running. So to make it more clear, I've edited the remaining post:
I went to neo4j-server.properties and uncommented:
org.neo4j.server.webserver.address=0.0.0.0
And start the server
NEO4J_HOME/bin/neo4j start
WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.
Using additional JVM arguments: -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled -XX:-OmitStackTraceInFastThrow
Starting Neo4j Server...WARNING: not changing user
process [28557]... waiting for server to be ready..... OK.
http://localhost:7474/ is ready.
checking the status:
NEO4J_HOME/bin/neo4j status
Neo4j Server is running at pid 28557
I can run the shell but the when I go to localhost 7474 I still can not connect
Any help would be appreciative. The only tutorial or help I've found assumed I was starting from scratch with a new instance. If someone could provide some instructions for installing or fix my configuration that would be great.
Thanks!
You have to edit neo4j-server.properties and uncomment the line with:
org.neo4j.server.webserver.address=0.0.0.0
So that the db listens on an external interface not just localhost, and you have to open the port (7474) in your firewall rules.
Make sure to secure access to the db though:
http://neo4j.com/docs/stable/security-server.html
I have to do distributed testing using JMeter. The objective is to have multiple remote servers in AWS controlled by one local server send a file download request to another server in AWS.
How can I set up the different servers in AWS?
How can I connect to them remotely?
Can someone provide some step by step instructions on how to do it?
I have tried several things but keep running into connectivity issues across networks.
We had a similar task and we ran into a bunch of issues as well. Here are the details of the whole process and what we did to resolve the issues we encountered. Hope it helps.
We needed to send requests from 5 servers located in various regions of the world. So we launched 5 micro instances in AWS, each in a different region. We chose the regions to be as geographically apart as possible.
Remote (server) JMeters config
Here is how we set up each instance.
Installed java:
$ sudo apt-get update
$ sudo apt-get install default-jre
Installed JMeter:
$ mkdir jmeter
$ cd jmeter;
$ wget ftp://apache.mirrors.pair.com//jmeter/binaries/apache-jmeter-2.9.tgz
$ gunzip apache-jmeter-2.9.tgz;tar xvf apache-jmeter-2.9.tar
Edited the jmeter.properties file in the /bin folder of the JMeter installation and uncomment the line containing the server.rmi.localport setting. We changed the port to 50000.
server.rmi.localport=50000
Started JMeter server. Make sure the address and the port the server reports listening to are correct.
$ cd ~/jmeter/apache-jmeter-2.9/bin
$ vi jmeter-server
Local (client) JMeter config
Then we set up JMeter to run tests remotely on these instances on our local client machine:
Ensured to use the same version of JMeter as was running on the servers. Installed Java and JMeter as described above.
Enabled remote testing by editing the jmeter.properties file that can be found in the bin folder of the JMeter installation. The parameter remote_hosts needed to be set with the public DNS of the remote servers we were connecting to.
remote_hosts=54.x.x.x,54.x.x.x,54.x.x.x,54.x.x.x,54.x.x.x
We were now able to tell our client JMeter instance to run tests on any or all of our specified remote servers.
Issues and resolutions
Here are the issues we encountered and how we resolved them:
The client failed with:
ERROR - jmeter.engine.ClientJMeterEngine: java.rmi.ConnectException: Connection - refused to host: 127.0.0.1
It was due to the server host returning the private IP address as its address because of Amazon NAT.
We fixed this by setting the parameter RMI_HOST_DEF that the /usr/local/jmeter/bin/jmeter-server script includes in starting the server:
RMI_HOST_DEF=-Djava.rmi.server.hostname=54.xx.xx.xx
Now, the AWS instance returned the server’s external IP, and we could start the test.
When the server node attempted to return the result and tried to connect to the client, the server tried to connect to the external IP address of my local machine. But it threw a connection refused error:
2013/05/16 12:23:37 ERROR - jmeter.samplers.RemoteListenerWrapper: testStarted(host) java.rmi.ConnectException: Connection refused to host: xxx.xxx.xxx.xx;
We resolved this issue by setting up reverse tunnels at the client side.
First, we edited the jmeter.properties file in the /bin folder of the JMeter installation and uncommented the line containing the client.rmi.localport setting. We changed the port to 60000:
client.rmi.localport=60000
Then we connected to each of the servers using SSH, and setup a reverse tunnel to port 60000 on the client.
$ ssh -i ~/.ssh/54-x-x-x.us-east.pem -R 60000:localhost:60000 ubuntu#54.x.x.x
We kept each of these sessions open, as the JMeter server needs to be able to deliver the test results to the client.
Then we set up the JVM_ARGS environment variable on the client, in the jmeter.sh file in the /bin folder:
export JVM_ARGS="-Djava.rmi.server.hostname=localhost"
By doing this, JMeter will tell the servers to connect to localhost:60000 for delivering their results. This ends up being tunneled back to the client.
The SSH connections to the servers kept dropping after staying idle for a little bit. To prevent that from happening, we added a parameter to each of the SSH tunnel set up directing the client to wait 60 seconds before sending a null packet to the server to keep the connection alive:
$ ssh -i ~/.ssh/54-x-x-x.us-east.pem -o ServerAliveInterval=60 -R 60000:localhost:60000 ubuntu#54.x.x.x
(.ssh/config version of all required SSH settings:
Host 54.x.x.x
HostName 54.x.x.x
Port 22
User ubuntu
ServerAliveInterval 60
RemoteForward 127.0.0.1:60000 127.0.0.1:60000
IdentityFile ~/.ssh/54-x-x-x.us-east.pem
IdentitiesOnly yes
Just use ssh 54.x.x.x after setting this up.
)
I just went though this on openstack and found the same issues... no idea why the jmeter remoting documentation only covers half the required steps. You can do it without tunnels or touching the properties files.
You need
All nodes to advertise their public IP - on AWS/OS this defaults to the private IP
Ingress rules for the RMI port which defaults to 1099 - I use this
Ingress rules for the RMI "local" port which defaults to dynamic. Below I use 4001 for the client and 4000 for servers. The port can be the same but note the properties are different.
If you are using your workstation as the client you probably still need tunnels. Above Archana Aggarwal has good tips for tunnels.
Remote servers
Set java.rmi.server.hostname and server.rmi.localport inline or in the properties file.
jmeter-server -Djava.rmi.server.hostname=publicip -Dserver.rmi.localport=4000
Sneaky server on client
You can also run one on the same machine as the client. For clarity I've set java.rmi.server.hostname but left server.rmi.localport as dynamic
jmeter-server -Djava.rmi.server.hostname=localip
Client
Set java.rmi.server.hostname and client.rmi.localport inline or in the properties file. Use -R etc like so:
jmeter -n -t Test.jmx -Rremotepublicip1,remotepublicip2 -Djava.rmi.server.hostname=clientpublicip -Dclient.rmi.localport=4001 -GmypropA=1 -GmypropB=2 -lresults.jtl
When you go for distributed testing using JMeter in AWS, I would suggest you to use docker - which will help us with jmeter test infrastructure very quickly. This way we can also ensure that same version of java and jmeter are installed in all the instances of amazon which is very important of JMeter distributed testing.
Ensure that - you set below properties and ports are open for jmeter-server. [they do not have to be 1099,50000 exactly]
server.rmi.localport=50000
server_port=1099
java.rmi.server.hostname=SERVER_IP
for client
client.rmi.localport=60000
java.rmi.server.hostname=SERVER_IP - this step is very important as the container in aws instance will have their own IP address in the docker network - so master and slave can not communicate. So we explicitly set this property
More info:
http://www.testautomationguru.com/jmeter-distributed-load-testing-using-docker-in-aws/