dhis2-users team mailing list archive

[Jason Phillips <jason@xxxxxxxx>]

Thanks, Lars!



I read it, but was under the impression that those features are part of the
paid version only, and we don’t have that (yet).

It does look interesting, and we’ll definitely be investigating more…  I’ll
let you know how it all pans out.

As it is, we have a five-server setup running currently, using ip_hash
weighted balancing.  It’s far from perfect, since the IP on mobiles changes
more often than copper/DSL, but it is working.  We’ve got a bit of work to
do to make it more streamlined, but we’re getting there… J



Kind Regards,

*Jason Phillips*

[image: hisp]
*Information Systems / Infrastructure*

*Health Information Systems Program____________________________________*

eMail:               jason@xxxxxxxx
Tel/Fax:            +27 21 712 0170
Cell:                 +27 72 973 7250
Skype:             jason.n.phillips

This message and any attachments are subject to a disclaimer published at
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*From:* Lars Helge Øverland [mailto:lars@xxxxxxxxx]
*Sent:* Wednesday, 16 March 2016 1:23 PM
*To:* Jason Phillips
*Cc:* DHIS 2 Users list
*Subject:* Re: [Dhis2-users] Load-balancing DHIS2 Webservers



Hi Jason,



there is the concept of "sticky sessions" which should ensure that a user
is always sent to the same server throughout his session:



https://www.nginx.com/products/session-persistence/

http://nginx.org/en/docs/http/load_balancing.html



There are other issues with load balancing (session persistence in case a
server goes down, hibernate cache replication) but this could help.



regards,



Lars













On Tue, Mar 15, 2016 at 8:20 PM, Jason Phillips <jason@xxxxxxxx> wrote:

Aha!



A little more reading goes a long way…  ip_hash persistence appears to work
– I can log in, anyway.

For those of you interested, here’s the URL:
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#ip_hash



If I have anything more relevant to share, I will…



Kind Regards,

*Jason Phillips*

[image: hisp]
*Information Systems / Infrastructure*

*Health Information Systems Program____________________________________*

eMail:               jason@xxxxxxxx
Landline:          +27 21 712 0170
Mobile:             +27 72 973 7250
Skype:             jason.n.phillips

This message and any attachments are subject to a disclaimer published at
http://www.hisp.org/policies.html#comms_disclaimer.  Please read the
disclaimer before opening any attachment or taking any other action in
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*From:* Jason Phillips [mailto:jason@xxxxxxxx]
*Sent:* Tuesday, 15 March 2016 8:34 PM
*To:* DHIS 2 Users list
*Subject:* Load-balancing DHIS2 Webservers



Hi, community (and Oslo team),



I am trying to set up a load-balanced DHIS2 web-server system; we have a
web server that’s getting slaughtered with incoming data, and we want to
distribute the load to other physical servers.  I’ve done some
experimentation, a fair amount of web-trawling, and using a dedicated nginx
virtual server, have (semi)successfully set up a load-balancing model like
so:





My problem is that going through the load-balancer, I appear to need some
kind of setting that will “keep” me at the Web-Server I first started with
– the load-balancer is set to round-robin, currently, with the following
settings:



upstream dhis2 {

        server webserver1.dhis.hisp.org;

        server webserver2.dhis.hisp.org;

        }



server {

        listen 80;

        server_name www.hisp.org hisp.org;



        location / {

                include /etc/nginx/proxy_params;

                proxy_pass http://dhis2;

        }

        location /staging {

                include /etc/nginx/proxy_params;

                proxy_pass http://dhis2;

        }

        location /training {

                include /etc/nginx/proxy_params;

                proxy_pass http://dhis2;

        }

}



What’s happening is that I attempt to log in, and get immediately switched
“round-robin” style to the second server for the post (promptly getting the
“forgot password?” prompt).
Nett result: I can’t log in…

If I log in to either one of the webservers directly, everything is fine
and dandy, but going through the LB is a no-go, so far.  (I have noticed
some interesting behaviour from two web servers connected to the same Db,
and would be keen to hear what input anyone has on that score – bad idea?
If so, why?  And what can be done to address the issues? – but I shall save
that for a separate post…)



Has anyone done any research/experimentation/development with a
load-balancing model of DHIS2 in a web-server context?  I would be most
interested to hear input.



Kind Regards,

*Jason Phillips*

[image: hisp]
*Information Systems / Infrastructure*

*Health Information Systems Program____________________________________*

eMail:               jason@xxxxxxxx
Landline:          +27 21 712 0170
Mobile:             +27 72 973 7250
Skype:             jason.n.phillips

This message and any attachments are subject to a disclaimer published at
http://www.hisp.org/policies.html#comms_disclaimer.  Please read the
disclaimer before opening any attachment or taking any other action in
terms of this electronic transmission.  If you cannot access the
disclaimer, kindly send an email to disclaimer@xxxxxxxx and a copy will be
provided to you. By replying to this e-mail or opening any attachment you
agree to be bound by the provisions of the disclaimer.





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-- 

Lars Helge Øverland

Lead developer, DHIS 2

University of Oslo

Skype: larshelgeoverland

http://www.dhis2.org <https://www.dhis2.org/>

-- 


*This message and any attachments are subject to a disclaimer published at 
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<http://www.hisp.org/policies.html#comms_disclaimer>.  Please read the 
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