dhis2-users team mailing list archive

[Lars Helge Øverland <lars@xxxxxxxxx>]

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