Hi,
On Mon, Jul 08, 2024 at 06:20:58PM +0400, Roman Arutyunyan wrote:
> Hi,
>
> On Thu, Jun 13, 2024 at 03:28:56PM -0700, Aleksei Bavshin wrote:
> > # HG changeset patch
> > # User Ruslan Ermilov <r...@nginx.com>
> > # Date 1392462754 -14400
> > # Sat Feb 15 15:12:34 2014 +0400
> > # Node ID 56aeae9355df8a2ee07e21b65b6869747dd9ee45
> > # Parent 02e9411009b987f408214ab4a8b6b6093f843bcd
> > Upstream: re-resolvable servers.
> >
> > Specifying the upstream server by a hostname together with the
> > "resolve" parameter will make the hostname to be periodically
> > resolved, and upstream servers added/removed as necessary.
> >
> > This requires a "resolver" at the "http" configuration block.
> >
> > The "resolver_timeout" parameter also affects when the failed
> > DNS requests will be attempted again. Responses with NXDOMAIN
> > will be attempted again in 10 seconds.
> >
> > Upstream has a configuration generation number that is incremented each
> > time servers are added/removed to the primary/backup list. This number
> > is remembered by the peer.init method, and if peer.get detects a change
> > in configuration, it returns NGX_BUSY.
> >
> > Each server has a reference counter. It is incremented by peer.get and
> > decremented by peer.free. When a server is removed, it is removed from
> > the list of servers and is marked as "zombie". The memory allocated by
> > a zombie peer is freed only when its reference count becomes zero.
> >
> > Re-resolvable servers utilize timers that also hold a reference. A
> > reference is also held while upstream keepalive caches an idle
> > connection.
> >
> > Co-authored-by: Roman Arutyunyan <a...@nginx.com>
> > Co-authored-by: Sergey Kandaurov <pluk...@nginx.com>
> > Co-authored-by: Vladimir Homutov <v...@nginx.com>
[..]
> > diff --git a/src/http/ngx_http_upstream_round_robin.h
> > b/src/http/ngx_http_upstream_round_robin.h
> > --- a/src/http/ngx_http_upstream_round_robin.h
> > +++ b/src/http/ngx_http_upstream_round_robin.h
> > @@ -14,8 +14,23 @@
> > #include <ngx_http.h>
> >
> >
> > +typedef struct ngx_http_upstream_rr_peers_s ngx_http_upstream_rr_peers_t;
> > typedef struct ngx_http_upstream_rr_peer_s ngx_http_upstream_rr_peer_t;
> >
> > +
> > +#if (NGX_HTTP_UPSTREAM_ZONE)
> > +
> > +typedef struct {
> > + ngx_event_t event; /* must be first */
> > + ngx_uint_t worker;
Missed this last time. This field should be removed since all resolving is in
worker #0.
> > + ngx_str_t name;
> > + ngx_http_upstream_rr_peers_t *peers;
> > + ngx_http_upstream_rr_peer_t *peer;
> > +} ngx_http_upstream_host_t;
> > +
> > +#endif
> > +
> > +
> > struct ngx_http_upstream_rr_peer_s {
> > struct sockaddr *sockaddr;
> > socklen_t socklen;
> > @@ -46,7 +61,12 @@ struct ngx_http_upstream_rr_peer_s {
> > #endif
> >
> > #if (NGX_HTTP_UPSTREAM_ZONE)
> > + unsigned zombie:1;
>
> I suggest declaring this as in other similar places:
>
> ngx_uint_t zombie; /* unsigned zombie:1; */
>
> > +
> > ngx_atomic_t lock;
> > + ngx_uint_t id;
>
> This field is not used in open source nginx and should not be added or
> assigned.
>
> > + ngx_uint_t refs;
> > + ngx_http_upstream_host_t *host;
> > #endif
> >
> > ngx_http_upstream_rr_peer_t *next;
[..]
--
Roman Arutyunyan
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