How do I set up remote access to a Blazegraph server?

Question

I try to remote access my Blazegraph server, which is running on a Ubuntu VM on Azure. So I want to access the server with its public IP address, e.g. 51.123.45.234:9999. I changed the firewall settings in Azure to allow incoming traffic to port 9999, but currently I can only access the server with:

curl 127.0.0.1:9999

or

curl localhost:9999

from the ssh shell when I connect to the server. I can't even connect with the server when I try the IP of the server on the connected ssh shell.

ifconfig
eth0  Link encap:Ethernet  HWaddr 00:0d:3a:28:cd:60
      inet addr:10.0.0.4  Bcast:10.0.0.255  Mask:255.255.255.0
      inet6 addr: fe80::20d:3aff:fe28:cd60/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:208531 errors:0 dropped:328 overruns:0 frame:0
      TX packets:178597 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:170613969 (170.6 MB)  TX bytes:28500224 (28.5 MB)

lo    Link encap:Local Loopback
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:6387 errors:0 dropped:0 overruns:0 frame:0
      TX packets:6387 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1
      RX bytes:565256 (565.2 KB)  TX bytes:565256 (565.2 KB)

The IP is the one of the virtual network the VM is in and not the public one. And if I try:

curl 10.0.0.4:9999

I get:

curl: (7) Failed to connect to 10.0.0.4 port 9999: Connection refused

I set up up my server following the instructions here. I also changed my .ssh/config to:

Host queryserver
LocalForward localhost:9999 127.0.0.1:9999

I also ran netstat to check if the server is listening:

netstat -ln | grep 9999
tcp6       0      0 127.0.0.1:9999          :::*                    LISTEN

My iptables shouldn't be the problem:

sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

How can I solve this problem?

Did you create an inbound security rule for the vm? – David Makogon Mar 26 '17 at 15:33 — David Makogon, Mar 26 '17 at 15:33
Yes, I added one to my network security group on azure. – user128574 Mar 26 '17 at 15:45 — user128574, Mar 26 '17 at 15:45

score 0 · Answer 1 · edited May 23 '17 at 11:54

tcp6       0      0 127.0.0.1:9999          :::*                    LISTEN

You could check your service is listening on tcp6 not tcp. For now, Azure does not support IPv6 on Azure VM directly. Azure only support IPv6 on Azure Load Balancer. More information please refer to this link.

If you want to access your service remotely, you could modify your service listening on tcp or use Azure Load Balancer.

You could refer to this similar question.

Igor Kim · Accepted Answer · 2017-03-28T06:05:31.980

Wikidata-query-rdf starts jetty servlet container and installs blazegraph-service-*.war, note that it specifies --host $HOST, which defaults to 'localhost' in runBlazegraph.sh script.

According to Jetty configuration, if --host specified, it defines the interface to listen on, so by default Blazegraph run by Wikidata-query-rdf listens only to localhost interface.

Specify -h your_ip while running runBlazegraph.sh :

./runBlazegraph.sh -h 10.0.0.4

If that does not resolve the issue, you might need to use 0.0.0.0 host name to listen on all interfaces and enable preferred IPv4 stack for java):

./runBlazegraph.sh -h 0.0.0.0 -o -Djava.net.preferIPv4Stack=true

How do I set up remote access to a Blazegraph server?

2 Answers2