Skip reverse DNS lookups

Author: yosifkit

5.5/Dockerfile

@@ -40,6 +40,8 @@ ENV PATH $PATH:/usr/local/mysql/bin:/usr/local/mysql/scripts
 RUN mkdir -p /etc/mysql/conf.d \
 	&& { \
 		echo '[mysqld]'; \
+		echo 'skip-host-cache'; \
+		echo 'skip-name-resolve'; \
 		echo 'user = mysql'; \
 		echo 'datadir = /var/lib/mysql'; \
 		echo '!includedir /etc/mysql/conf.d/'; \

5.6/Dockerfile

@@ -30,7 +30,10 @@ RUN { \
 	&& rm -rf /var/lib/mysql && mkdir -p /var/lib/mysql
 
 # comment out a few problematic configuration values
-RUN sed -Ei 's/^(bind-address|log)/#&/' /etc/mysql/my.cnf
+# don't reverse lookup hostnames, they are usually another container
+RUN sed -Ei 's/^(bind-address|log)/#&/' /etc/mysql/my.cnf \
+	&& echo 'skip-host-cache\nskip-name-resolve' | awk '{ print } $1 == "[mysqld]" && c == 0 { c = 1; system("cat") }' /etc/mysql/my.cnf > /tmp/my.cnf \
+	&& mv /tmp/my.cnf /etc/mysql/my.cnf
 
 VOLUME /var/lib/mysql
 

5.7/Dockerfile

@@ -30,7 +30,10 @@ RUN { \
 	&& rm -rf /var/lib/mysql && mkdir -p /var/lib/mysql
 
 # comment out a few problematic configuration values
-RUN sed -Ei 's/^(bind-address|log)/#&/' /etc/mysql/my.cnf
+# don't reverse lookup hostnames, they are usually another container
+RUN sed -Ei 's/^(bind-address|log)/#&/' /etc/mysql/my.cnf \
+	&& echo 'skip-host-cache\nskip-name-resolve' | awk '{ print } $1 == "[mysqld]" && c == 0 { c = 1; system("cat") }' /etc/mysql/my.cnf > /tmp/my.cnf \
+	&& mv /tmp/my.cnf /etc/mysql/my.cnf
 
 VOLUME /var/lib/mysql