haproxy + spring boot writeAddress(..) failed: Connection reset by peer - spring

Question

I'm running HAproxy with backend Spring Boot Rest controllers. My spring log shows constant errors that look like the following:
[reactor-http-epoll-26] ERROR o.s.w.s.a.HttpWebHandlerAdapter - [9df8bfcf] Error [io.netty.channel.unix.Errors$NativeIoException: writeAddress(..) failed: Connection reset by peer] for HTTP GET "/api/v1/status", but ServerHttpResponse already committed (200 OK)
HAproxy performs an HTTP check on the url /api/v1/status. What would be the reason that I'm getting these errors?
HAProxy Config
global
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
# daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
ssl-default-bind-ciphers EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH+aRSA+RC4:EECDH:EDH+aRSA:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EX$
ssl-default-bind-options no-sslv3 no-tlsv10
tune.ssl.default-dh-param 4096
defaults
mode http
log global
option httplog
option http-server-close
option forwardfor except 127.0.0.0
option redispatch
retries 3
timeout http-request 30s
timeout queue 1m
timeout connect 30s
timeout client 30s
timeout server 30s
frontend https-in
bind *:443 ssl crt /etc/cert.pem
default_backend api
backend api
mode http
option httpchk GET /api/v1/status HTTP/1.0
http-check expect status 200
balance roundrobin
server api1 127.0.0.1:8001 check fall 3 rise 2
server api2 127.0.0.1:8002 check fall 3 rise 2

Answer 1

HAproxy is doing GET request, reads http response code and closing connection.
Boot is trying to send remaining parts (http headers and some json payload) but connection is already closed.
Just replace GET with OPTIONS in the line:
option httpchk GET /api/v1/status HTTP/1.0