dhis2-users team mailing list archive

[Bob Jolliffe <bobjolliffe@xxxxxxxxx>]

I have not done this, but I imagine that hibernate cache replication
between instances is something that really needs to be done to have this
sort of scaling configuration work.

I do remember there was a brief flirtation with hazelcast before reverting
to ehcache.  Is anybody using ehcache in this way ie. for replication in a
clustering setup?

On 16 March 2016 at 12:22, Lars Helge Øverland <lars@xxxxxxxxx> wrote:

> 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/>
>
>
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>