better key server access

[aboettger-tuhh]

+ gpg --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
gpg: keyring `/tmp/tmp.xRaHS50qFg/secring.gpg' created
gpg: keyring `/tmp/tmp.xRaHS50qFg/pubring.gpg' created
gpg: requesting key BF357DD4 from hkp server ha.pool.sks-keyservers.net
gpg: keyserver timed out
gpg: keyserver receive failed: keyserver error

[yosifkit]

GPG keyservers being flaky is a problem we see all too often -- closing since there's not really anything actionable here. As a workaround, I'd recommend either pulling the pre-built images as-is (and perhaps building upon them via FROM mysql:XXX in a derivative Dockerfile) or adjusting the keyserver to one which your own local environment has an easier time fetching from (such as hkp://keyserver.ubuntu.com:80 or similar).

- docker-library/mysql#263 (comment)

Related issues: docker-library/cassandra#131 (comment), docker-library/tomcat#87, docker-library/tomcat#108, docker-library/mysql#263 (comment), docker-library/httpd#66 (comment), docker-library/php#586, docker-library/wordpress#291