[PATCH] Make random/hash director exhaust the backend list when looking for healthy backend.
Federico Schwindt
fgsch at lodoss.net
Fri Aug 29 15:10:39 CEST 2014
Hi,
Any reason not to use rr->vd->n_backend directly as the round-robin
director does?
On Fri, Aug 29, 2014 at 1:48 PM, Martin Blix Grydeland <
martin at varnish-software.com> wrote:
> Fixes: #1575
> ---
> bin/varnishtest/tests/r01575.vtc | 56
> ++++++++++++++++++++++++++++++++++++++++
> lib/libvmod_directors/hash.c | 6 ++---
> lib/libvmod_directors/random.c | 6 ++---
> lib/libvmod_directors/vdir.c | 2 +-
> 4 files changed, 63 insertions(+), 7 deletions(-)
> create mode 100644 bin/varnishtest/tests/r01575.vtc
>
> diff --git a/bin/varnishtest/tests/r01575.vtc
> b/bin/varnishtest/tests/r01575.vtc
> new file mode 100644
> index 0000000..11c82c1
> --- /dev/null
> +++ b/bin/varnishtest/tests/r01575.vtc
> @@ -0,0 +1,56 @@
> +varnishtest "#1575 - random director exhaust backend list"
> +
> +# Add 5 backends to a random director, with the 5th having very low
> weight.
> +# Mark the first 4 sick, and make sure that the 5th will be selected.
> +
> +server s1 {
> + rxreq
> + txresp
> +} -start
> +
> +server s2 {
> + rxreq
> + txresp
> +} -start
> +
> +server s3 {
> + rxreq
> + txresp
> +} -start
> +
> +server s4 {
> + rxreq
> + txresp
> +} -start
> +
> +server s5 {
> + rxreq
> + txresp
> +} -start
> +
> +varnish v1 -vcl+backend {
> + import ${vmod_directors};
> + sub vcl_init {
> + new rd = directors.random();
> + rd.add_backend(s1, 10000);
> + rd.add_backend(s2, 10000);
> + rd.add_backend(s3, 10000);
> + rd.add_backend(s4, 10000);
> + rd.add_backend(s5, 1);
> + }
> +
> + sub vcl_backend_fetch {
> + set bereq.backend = rd.backend();
> + }
> +} -start
> +
> +varnish v1 -cliok "backend.set_health s1 sick"
> +varnish v1 -cliok "backend.set_health s2 sick"
> +varnish v1 -cliok "backend.set_health s3 sick"
> +varnish v1 -cliok "backend.set_health s4 sick"
> +
> +client c1 {
> + txreq
> + rxresp
> + expect resp.status == 200
> +} -run
> diff --git a/lib/libvmod_directors/hash.c b/lib/libvmod_directors/hash.c
> index afef7ed..090039f 100644
> --- a/lib/libvmod_directors/hash.c
> +++ b/lib/libvmod_directors/hash.c
> @@ -47,7 +47,7 @@ struct vmod_directors_hash {
> unsigned magic;
> #define VMOD_DIRECTORS_HASH_MAGIC 0xc08dd611
> struct vdir *vd;
> - unsigned nloops;
> + unsigned n_backend;
> struct vbitmap *vbm;
> };
>
> @@ -64,7 +64,6 @@ vmod_hash__init(const struct vrt_ctx *ctx, struct
> vmod_directors_hash **rrp,
> AN(rr);
> rr->vbm = vbit_init(8);
> AN(rr->vbm);
> - rr->nloops = 3; //
> *rrp = rr;
> vdir_new(&rr->vd, vcl_name, NULL, NULL, rr);
> }
> @@ -90,6 +89,7 @@ vmod_hash_add_backend(const struct vrt_ctx *ctx,
> CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
> CHECK_OBJ_NOTNULL(rr, VMOD_DIRECTORS_HASH_MAGIC);
> (void)vdir_add_backend(rr->vd, be, w);
> + rr->n_backend++;
> }
>
> VCL_BACKEND __match_proto__()
> @@ -120,6 +120,6 @@ vmod_hash_backend(const struct vrt_ctx *ctx, struct
> vmod_directors_hash *rr,
> r = vbe32dec(sha256);
> r = scalbn(r, -32);
> assert(r >= 0 && r <= 1.0);
> - be = vdir_pick_be(rr->vd, r, rr->nloops);
> + be = vdir_pick_be(rr->vd, r, rr->n_backend);
> return (be);
> }
> diff --git a/lib/libvmod_directors/random.c
> b/lib/libvmod_directors/random.c
> index 22f0bb9..8ae36a7 100644
> --- a/lib/libvmod_directors/random.c
> +++ b/lib/libvmod_directors/random.c
> @@ -45,7 +45,7 @@ struct vmod_directors_random {
> unsigned magic;
> #define VMOD_DIRECTORS_RANDOM_MAGIC 0x4732d092
> struct vdir *vd;
> - unsigned nloops;
> + unsigned n_backend;
> struct vbitmap *vbm;
> };
>
> @@ -68,7 +68,7 @@ vmod_rr_getfd(const struct director *dir, struct busyobj
> *bo)
> CAST_OBJ_NOTNULL(rr, dir->priv, VMOD_DIRECTORS_RANDOM_MAGIC);
> r = scalbn(random(), -31);
> assert(r >= 0 && r < 1.0);
> - be = vdir_pick_be(rr->vd, r, rr->nloops);
> + be = vdir_pick_be(rr->vd, r, rr->n_backend);
> if (be == NULL)
> return (NULL);
> return (be->getfd(be, bo));
> @@ -87,7 +87,6 @@ vmod_random__init(const struct vrt_ctx *ctx, struct
> vmod_directors_random **rrp,
> AN(rr);
> rr->vbm = vbit_init(8);
> AN(rr->vbm);
> - rr->nloops = 3; //
> *rrp = rr;
> vdir_new(&rr->vd, vcl_name, vmod_rr_healthy, vmod_rr_getfd, rr);
> }
> @@ -113,6 +112,7 @@ vmod_random_add_backend(const struct vrt_ctx *ctx,
> CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
> CHECK_OBJ_NOTNULL(rr, VMOD_DIRECTORS_RANDOM_MAGIC);
> (void)vdir_add_backend(rr->vd, be, w);
> + rr->n_backend++;
> }
>
> VCL_BACKEND __match_proto__()
> diff --git a/lib/libvmod_directors/vdir.c b/lib/libvmod_directors/vdir.c
> index 12268eb..aae7a14 100644
> --- a/lib/libvmod_directors/vdir.c
> +++ b/lib/libvmod_directors/vdir.c
> @@ -186,7 +186,7 @@ vdir_pick_be(struct vdir *vd, double w, unsigned
> nloops)
> nbe = vd->n_backend;
> assert(w >= 0.0 && w < 1.0);
> vdir_lock(vd);
> - for (l = 0; nbe > 0 && tw > 0.0 && l <nloops; l++) {
> + for (l = 0; nbe > 0 && tw > 0.0 && l < nloops; l++) {
> u = vdir_pick_by_weight(vd, w * tw, vbm);
> be = vd->backend[u];
> CHECK_OBJ_NOTNULL(be, DIRECTOR_MAGIC);
> --
> 2.1.0.rc1
>
>
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> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-dev
>
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