如何删除overlay2以及docker pull的多余的镜像？

Question

用git pull了一个canal v1.1.1
好像装了两次
发现在/var/lib/docker 貌似有两份

# du -m|grep canal
54      ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/lib
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/bin
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/logs
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/spring/tsdb/sql
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/spring/tsdb/sql-map
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/spring/tsdb
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/spring
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/metrics
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf/example
1       ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server/conf
54      ./overlay2/b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd/diff/home/admin/canal-server
54      ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/lib
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/bin
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/spring/tsdb/sql
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/spring/tsdb/sql-map
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/spring/tsdb
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/spring
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/metrics
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf/example
1       ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server/conf
54      ./overlay2/8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea/diff/home/admin/canal-server

但是docker images发现只有一个，我不知道这个image对应的是上面的8690f9a5865ca8582fb0a3eb1b50fd7b34b1825dd6d922183b40c8d7f2bb7dea还是b9b36e843a6ee1b2372051de27cb08a714739bba83b1fd4d78c0cec2c5cf7dcd

# docker images
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
canal/canal-server       v1.1.1              008e1d7824e1        12 months ago       831MB

请问如何删除上面overlay2下多余的文件？
另外，假如我要删除docker pull下来的v1.1.1,如何做？