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| -rw-r--r-- | doc/seamless_reload.txt | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/doc/seamless_reload.txt b/doc/seamless_reload.txt new file mode 100644 index 0000000..94df1bd --- /dev/null +++ b/doc/seamless_reload.txt @@ -0,0 +1,62 @@ +Reloading HAProxy without impacting server states +================================================= + +Of course, to fully understand below information please consult +doc/configuration.txt to understand how each HAProxy directive works. + +In the mean line, we update HAProxy's configuration to tell it where to +retrieve the last know trustable servers state. +Then, before reloading HAProxy, we simply dump servers state from running +process into the locations we pointed into the configuration. +And voilà :) + + +Using one file for all backends +------------------------------- + +HAProxy configuration +********************* + + global + [...] + stats socket /var/run/haproxy/socket + server-state-file global + server-state-base /var/state/haproxy/ + + defaults + [...] + load-server-state-from-file global + +HAProxy init script +******************* + +Run the following command BEFORE reloading: + + socat /var/run/haproxy/socket - <<< "show servers state" > /var/state/haproxy/global + + +Using one state file per backend +-------------------------------- + +HAProxy configuration +********************* + + global + [...] + stats socket /var/run/haproxy/socket + server-state-base /var/state/haproxy/ + + defaults + [...] + load-server-state-from-file local + +HAProxy init script +******************* + +Run the following command BEFORE reloading: + + for b in $(socat /var/run/haproxy/socket - <<< "show backend" | fgrep -v '#') + do + socat /var/run/haproxy/socket - <<< "show servers state $b" > /var/state/haproxy/$b + done + |