We Keep Coding

How to specify gRPC server address target on client side when the service is on format <my-service:port>

We are using grpc spring boot starter on our Java application service in order to establish a connection to another 'server' service, so I define in the application.properties the following address:
grpc.client.name.address=static://service-name:port
When tried to connect it I got the following error message:
StatusRuntimeException: UNAVAILABLE: io exception
So I know for sure I have a connectivity issue. On the documentation it says regarding the static scheme:
A simple static list of IPs (both v4 and v6), that can be use connect to the server
So I guess this is not what I need to use. It seems the best option in my case is using the discovery scheme, but it doesn't contains any port...
What is the right scheme configuration I need to use to set the server address?

Wanted to share the resolution for this very annoying issue for those who will encounter the same problem in the future like I did.
So first, the scheme needs to be set indeed of dns type, like the following: grpc.client._name_.address=dns:///<service-name>:26502
but this alone is not enough. (at least in my case) The server was configured to run in PLAINTEXT, while my client, by default, was configured to run with TLS mode, so it must be set with grpc.client.__name__.negotiationType=PLAINTEXT property.
See the following documentation for further information

It caused by gRPC can't resolve addresss service-name:port;
If you use static, the value must be ip:port; The service-name need to be resolved as ip address;
If you are using register center like consul or eureka etc., you should use discovery:///service-name without specify port.
If you didn't use register center, only end to end with server, replace service-name as a ip like 127.0.0.1 which belong to server;
Or modify host config for parse service-name like below, the file on Linux is /etc/hosts
127.0.0.1 service-name

Azure and Apache Mina

I am not sure whether this question is Mina-related or more Azure-related but it has to do with the networking. I have also added Netty tag since Mina and Netty share many networking principles.
I hope to get an advice where to dig into.
I have used certain Mina application quite long in local network, now I am trying to migrate it into the cloud. I deploy Linux virtual machines in Azure (each has public IP but does this really matter?).
They connect (using Mina) to a machine outside Azure that also has its
own public IP. Usual thing:
SocketConnector connector = new NioSocketConnector(numberOfConnectors);
ConnectFuture connectFuture = connector.connect(new
InetSocketAddress(remoteHost, remotePort));
connectFuture.awaitUninterruptibly(connectTimeout);
That Mina machine outside the Azure also runs Mina. Let's call it
server machine.
It accepts connections like this:
NioSocketAcceptor acceptor = new NioSocketAcceptor(acceptor_threads);
org.apache.mina.core.buffer.IoBuffer.setUseDirectBuffer(false);
acceptor.getSessionConfig().setTcpNoDelay(true);
acceptor.setReuseAddress(true);
acceptor.getSessionConfig().setSendBufferSize(buffer_size);
acceptor.getSessionConfig().setMinReadBufferSize(64000);
acceptor.getSessionConfig().setReceiveBufferSize(buffer_size);
acceptor.getSessionConfig().setIdleTime(IdleStatus.BOTH_IDLE, iddle_time);
acceptor.getFilterChain().addLast("codec", new
ProtocolCodecFilter(CodecFactory.getInstance()));
acceptor.setDefaultLocalAddress(new InetSocketAddress(port));
When Azure applications connect to server machine, server saves
IoSession session
to asynchronously push messages back in future like this:
session.write(message);
This worked well inside a local network (without Azure), but in current
deployment server sends message
2017-01-17/15:45:19.823/GMT-00:00 [nioEventLoopGroup-3-3] [...] DEBUG
Sending message to /13.94.143.139:41790
and an Azure machine does not receive anything. Moreover, after a
while the following exception arises on server machine:
2017-01-17/16:01:11.419/GMT-00:00 [NioProcessor-4] [...] ERROR
Exception in IOHandlerConnection timed out
java.io.IOException: Connection timed out
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:197)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:280)
at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:44)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:695)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:668)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:657)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$600(AbstractPollingIoProcessor.java:68)
at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:1141)
at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
2017-01-17/16:01:11.424/GMT-00:00 [NioProcessor-3] [...] DEBUG sessionClosed
I use Mina version 2.0.4 (yes, it is old but it works on local network for several years for now).
I setup Azure network with Java Azure SDK 1.0.0-beta3
Network.DefinitionStages.WithCreate creatableNetwork = azure.networks()
.define(networkName)
.withRegion(region)
.withExistingResourceGroup(resourceGroup)
.withAddressSpace("10.0.0.0/20");
And create virtual machines as
VirtualMachine.DefinitionStages.WithCreate creatableVirtualMachine =
azure.virtualMachines()
.define(String.format(...))
.withRegion(region)
.withExistingResourceGroup(resourceGroup)
.withNewPrimaryNetwork(creatableNetwork)
.withPrimaryPrivateIpAddressStatic(inetAddress.getHostAddress())
.withNewPrimaryPublicIpAddress(String.format("chr-vm-%04d", i)) .withPopularLinuxImage(KnownLinuxVirtualMachineImage.UBUNTU_SERVER_16_04_LTS)
.withRootUserName(linuxUserName)
.withPassword(linuxUserPassword)
.withSize(VirtualMachineSizeTypes.STANDARD_D2_V2)
.withNewStorageAccount(creatableStorageAccount);
I wonder what reasons may prevent traveling messages from server to
Azure client machines? Azure network configuration? Mina configuration? (the first messages from client machines to server machine do come after they connect)
I hope that above information may contain a clue.

I have solved my problem thanks to Peter Pan - MSFT noting about NSG - Network Security Group.
NSG controls in/out rules like a Windows Firewall. You should create NSG, add rules to it, and assign NSG to a particular entity:
There are at least two options to assign NSG:
to a network subnet
to a network interface
There is a tutorial 1 and Java code sample 2. In my case, a separate network interface is created for each VM (since each VM has public IP). So, I assigned one NSG to a single subnet.
Fisrt, create NSG:
NetworkSecurityGroup NSG = azure.networkSecurityGroups()
.define(networkSecurityGroup)
.withRegion(region)
.withExistingResourceGroup(resourceGroup)
.defineRule("Inbound")
.allowInbound()
.fromAnyAddress()
.fromAnyPort()
.toAnyAddress()
.toAnyPort()
.withAnyProtocol()
.withDescription("Incoming messsages")
.withPriority(100)
.attach()
.create();
Than modify the code to explicitly define a subnet and assign NSG to it ( subnet1 is automatically created without NSG if none defined explicitly)
Network.DefinitionStages.WithCreate creatableNetwork = azure.networks()
.define(networkName)
.withRegion(region)
.withExistingResourceGroup(resourceGroup)
.withAddressSpace("10.0.0.0/20")
.defineSubnet(subnetName)
.withAddressPrefix("10.0.0.0/20")
.withExistingNetworkSecurityGroup(NSG)
.attach();
So, the rest of the code remains the same as posted in the question above.
Helpful links:
Azure Portal Tutorial
Java Azure SDK NSG Example

Not able to connect to remote cassandra

I am trying to access Cassandra(2.1.0) installed on my machine from other machine using my ip address. Here is how I am trying to do it in other machine:
Cluster cluster = Cluster.builder().addContactPoint("192.168.3.51").build();
Session session = cluster.connect("adaequare");
But I am not able to access it. Here are few configurations from Cassandra installed on my machine:
listen_address: localhost
start_native_transport: true
native_transport_port: 9042
rpc_address: localhost
rpc_port: 9160
I tried changing localhost to my ip address. But it did not work either. Do I have to make any other changes in my cassandra.yaml to get this done?

You need to post the error. By saying "It didn't work" gives no clue at all.
Anyway, rpc_addressin cassandra.yaml should point to the IP you configured. In case it is 192.168.3.51, then it needs to go there.

Elasticsearch server discovery configuration

I've installed ElasticSearch server, that i'm running by:
$ ./elasticsearch -f
{0.18.2}[11698]: initializing ...
loaded [], sites []
{0.18.2}[11698]: initialized
{0.18.2}[11698]: starting ...
bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/192.168.1.106:9300]}
new_master [Stingray][ocw4qPdmSfWuD9pUxHoN1Q][inet[/192.168.1.106:9300]], reason: zen-disco-join (elected_as_master)
elasticsearch/ocw4qPdmSfWuD9pUxHoN1Q
recovered [0] indices into cluster_state
bound_address {inet[/0:0:0:0:0:0:0:0:9200]}, publish_address {inet[/192.168.1.106:9200]}
{0.18.2}[11698]: started
How I can configure Java client to connect to this server?
I have just:
node.client=true
but, after trying to connect i'm receiving:
org.elasticsearch.discovery.MasterNotDiscoveredException:
at org.elasticsearch.action.support.master.TransportMasterNodeOperationAction$3.onTimeout(TransportMasterNodeOperationAction.java:162)
If i'm configuring java client as:
node.data=false
I'm getting following logs:
INFO main node:internalInfo:93 - [Stark, Tony] {0.18.2}[13008]: starting ...
INFO main transport:internalInfo:93 - [Stark, Tony] bound_address {inet[/0:0:0:0:0:0:0:0:9301]}, publish_address {inet[/192.168.1.106:9301]}
INFO elasticsearch[Stark, Tony]clusterService#updateTask-pool-13-thread-1 service:internalInfo:93 - [Stark, Tony] new_master [Stark, Tony][WkNn96hgTkWXRnsR0EOZjA][inet[/192.168.1.106:9301]]{data=false}, reason: zen-disco-join (elected_as_master)
As I understood it means that this new node (supposed to be client node) made itself a new master node. And I don't from log that it's found and connect to any other node.
Both server and client are started on same machine. 192.168.1.106:9200 are accessible from browser.
And I can't find any good documentation about discovery config. Where I can read more about ElasticSearch configurations? And how to configure Java client?

The most likely reason for this failure is firewall on your machine that blocks multicast discovery traffic on port 54328. Both client and master are broadcasting on this port during initial discovery and they don't hear back from each other. That's why when you specify node.client=true client node (that cannot be a master) fails with MasterNotDiscoveredException and node with no data elects itself as a master.

I ran into the same problem and by using IP numbers in the config file resolved it for me.
in /config/elasticsearch.yml
uncomment and change the network.host setting to:
network.host: 127.0.0.1
You can also change this to your machine IP number in ifconfig.

I had the same issue. Eventually, it turned out I had a firewall issue, with my firewall (on Ubuntu) blocking the ports of ElasticSearch. I'm using the default firewall on Ubuntu, ufw.
So, to open up the ports, I ran these commands on the terminal:
sudo ufw allow proto tcp to any port 9200:9400
sudo ufw allow proto tcp to any port 54328
My cluster runs locally on 9200, and all my clients open up on 9300+. So, I just opened the range 9200-9400 for them. 54328 is for the multicast broadcast.
Just to be complete: I also used the TransportClient, which works, but I added hardcoded my localhost to the address the TransportClient will work on. Not a good thing for production code :-)

Faced the same issue where the nodes were not able to elect a master on nodes restart.
The problem lies in the communication of nodes among themselves.
Please ensure in your elastic search logs, whether the node restart says
publish_address {127.0.0.1:9200}
or
publish_address {0.0.0.1:9200}
This means the current node is not publishing its IP address to other nodes and hence the nodes won't recognise this node even though the node IP might be present in the discovery.zen.ping.unicast.hosts
Solution
Make the following changes in elasticsearch.yml. Add
network.host: _non_loopback:ipv4_
and restart the node.
Ensure that the bound address now shows the <IP address>:<port no> and not the localhost.
This means that now your node is discoverable. The second step to make it discoverable in the cluster is to add the ip address of the node in the unicast hosts lists of all the master nodes, so that whenever we have a new master, the node is discoverable to the new master.
Add the node IP to the discovery.zen.ping.unicast.hosts
list of hosts of all the masters to make it disoverable. A masterpings all the
nodes present in the unicast list.

Something like this should work:
Settings s = ImmutableSettings.settingsBuilder()
.put(this.settings)
.build();
TransportClient client = new TransportClient(s);
client.addTransportAddress(new InetSocketTransportAddress(
"localhost",
9300)
);
What fouled me up was I originally tried connecting the client to 9200, not 9300. Guidance for settings above can be found from http://www.elasticsearch.org/guide/reference/java-api/client.html

Configure network host to localhost:
network.host: 127.0.0.1

UnknkownHostException

Please help;
Am trying to deploy a web application.
The build is returning successful,and am not getting any errors on the sever.log
however am getting a http 503 error:the requested service() is not currently available
and also my
Java DB Database Process has this message
Warning: UnknkownHostException: intracare: intracare.
Could not listen on port 1527 on host localhost.
am using glassfish v3 prelude

Possibly you already have another application (perhaps another JavaDB instance?) listening on port 1527 - that could explain the "could not listen" message. Use netstat to check.

I think that UnknownHostException is related that intracare can't be resolved to an IP.
I would:
Ping that host.
Check C:\WINDOWS\system32\drivers\etc\hosts or /etc/hosts files.
Regards.

Check the DNS settings on the host. Your short names do not resolve correctly.

Mayby string you are typing as a host name is wrong? Maybe it is firewall problem?