Does EMS server/client cache IP Addresses?
Article ID: KB0091018
Updated On:
| Products | Versions |
|---|---|
| TIBCO Enterprise Message Service | - |
| Not Applicable | - |
Description
Resolution:
Description:
= = = = = = = =
Does EMS server/client cache IP Addresses? If the host IP address is changed, do I need to restart EMS server/clients?
Resolution
=========
For the client, it is true that each connection results in a hostname lookup. EMS uses gethostname() to find its host name. It then uses gethostbyname() to find its IP address.
Neither EMS server nor EMS clients caches that resolved IP address in the memory or meta.db file.
If you have client connections from other machines that are using the hostname to connect, you will not have any problems reconnecting automatically when a change in the IP of the host where EMS is running is done.
If you bring down a machine with an EMS server running on it, change the IP address, restart the machine and restart the EMS server, any FT clients or other EMS servers should resolve the new mapping and be able to reconnect to the newly started EMS server.
EMS uses gethostbyname() to find its IP address. A OS DNS flush may be be needed.
The server does cache IP addresses. This is relevant for routes. A FT standby server will do the name resolution to reconnect to the active server.For the route, the cached IP of a routed server is flushed after 60 seconds of a failure to reconnect to that server. If using IP Address, instead of hostname, verify the following:
Check the following:
In file tibemsd.conf parameters listen and ft_active. Also if you are using FT, you have to check the tibemsd.conf file of the other EMS server running in other machine to point to the new IP (if the IP is used in the ft_active instead of the hostname).
If using connection factories or routes, check the files routes.conf and factories.conf files. You can also do this with “show routes” and “show factories” using the admin tool to check in which places you are using the IP and change it to the new one.
If using routes, also check the configuration of the EMS servers that are neighbours running in other hosts. You have to change the routes defined in other EMS servers (in other hosts) to point to the new IP.
Remember to add the IP map in /etc/hosts file of the OS and also in the /etc/hosts of other hosts.
You will need to restart the EMS server and/or clients.
Description:
= = = = = = = =
Does EMS server/client cache IP Addresses? If the host IP address is changed, do I need to restart EMS server/clients?
Resolution
=========
For the client, it is true that each connection results in a hostname lookup. EMS uses gethostname() to find its host name. It then uses gethostbyname() to find its IP address.
Neither EMS server nor EMS clients caches that resolved IP address in the memory or meta.db file.
If you have client connections from other machines that are using the hostname to connect, you will not have any problems reconnecting automatically when a change in the IP of the host where EMS is running is done.
If you bring down a machine with an EMS server running on it, change the IP address, restart the machine and restart the EMS server, any FT clients or other EMS servers should resolve the new mapping and be able to reconnect to the newly started EMS server.
EMS uses gethostbyname() to find its IP address. A OS DNS flush may be be needed.
The server does cache IP addresses. This is relevant for routes. A FT standby server will do the name resolution to reconnect to the active server.For the route, the cached IP of a routed server is flushed after 60 seconds of a failure to reconnect to that server. If using IP Address, instead of hostname, verify the following:
Check the following:
In file tibemsd.conf parameters listen and ft_active. Also if you are using FT, you have to check the tibemsd.conf file of the other EMS server running in other machine to point to the new IP (if the IP is used in the ft_active instead of the hostname).
If using connection factories or routes, check the files routes.conf and factories.conf files. You can also do this with “show routes” and “show factories” using the admin tool to check in which places you are using the IP and change it to the new one.
If using routes, also check the configuration of the EMS servers that are neighbours running in other hosts. You have to change the routes defined in other EMS servers (in other hosts) to point to the new IP.
Remember to add the IP map in /etc/hosts file of the OS and also in the /etc/hosts of other hosts.
You will need to restart the EMS server and/or clients.
Issue/Introduction
Does EMS server/client cache IP Addresses?
Feedback
Yes
No
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