问题
I have a vagrant box on debian/stretch64 I try to install Hadoop3 with documentation http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/SingleCluster.htm
When I run start-dfs.sh I have this message
vagrant@stretch:/opt/hadoop$ sudo sbin/start-dfs.sh
Starting namenodes on [localhost]
pdsh@stretch: localhost: connect: Connection refused
Starting datanodes
pdsh@stretch: localhost: connect: Connection refused
Starting secondary namenodes [stretch]
pdsh@stretch: stretch: connect: Connection refused
vagrant@stretch:/opt/hadoop$
of course I tried to update my hadoop-env.sh with : export HADOOP_SSH_OPTS="-p 22"
ssh localhost work (without password)
I have not ideas what I can change to solve this problem
回答1:
There is a problem the way pdsh works by default (see edit), but Hadoop can go without it. Hadoop checks if the system has pdsh on /usr/bin/pdsh and uses it if so. An easy way get away from using pdsh is editing $HADOOP_HOME/libexec/hadoop-functions.sh
replace the line
if [[ -e '/usr/bin/pdsh' ]]; then
by
if [[ ! -e '/usr/bin/pdsh' ]]; then
then hadoop goes without pdsh and everything works.
EDIT:
A better solution would be use pdsh, but with ssh instead rsh as explained here, so replace line from $HADOOP_HOME/libexec/hadoop-functions.sh:
PDSH_SSH_ARGS_APPEND="${HADOOP_SSH_OPTS}" pdsh \
by
PDSH_RCMD_TYPE=ssh PDSH_SSH_ARGS_APPEND="${HADOOP_SSH_OPTS}" pdsh \
Obs: Only doing export PDSH_RCMD_TYPE=ssh, as I mention in the comment, doesn't work. I don't know why...
I've also opened a issue and submitted a patch to this problem: HADOOP-15219
回答2:
Check if the firewalls are running on your vagrant box
chkconfig iptables off
/etc/init.d/iptables stop
if not that have a look in the underlying logs /var/log/...
回答3:
I fixed this problem for hadoop 3.1.0 by adding
PDSH_RCMD_TYPE=ssh
in my .bashrc as well as $HADOOP_HOME/etc/hadoop/hadoop-env.sh.
来源：https://stackoverflow.com/questions/48189954/hadoop-start-dfs-sh-connection-refused