Apache経由でMattermostを使いたいとき ref: http://qiita.com/YuzuRyo61/items/d5c9f04f4587b753d53a

Add

Header add Upgrade "Websocket"
Header add Connection "Upgrade"
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / "ws://localhost:8065/"
ProxyPassReverse / "ws://localhost:8065/"

Invalid

ProxyRequests Off
ProxyPreserveHost On
ProxyPass / "http://localhost:8065/"
ProxyPassReverse / "http://localhost:8065/"

log

[YYYY/MM/DD {TIME} JST] [EROR] github.com/mattermost/platform/api.connect:31 :: ウェブソケット接続エラー: websocket: could not find connection header with token 'upgrade'

My Setting

<VirtualHost team.example.com:80>
DocumentRoot "/var/www/html"
ServerName team.example.com
RewriteEngine on
RewriteRule ^(.*)$ https://team.example.com/ [R=301,L]
<Directory "/var/www/html">
allow from all
Require all granted
</Directory>
</VirtualHost>
<VirtualHost team.example.com:443>
DocumentRoot "/var/www/html"
ServerName team.example.com:443
<Directory "/var/www/html">
allow from all
Require all granted
</Directory>
Header always set Strict-Transport-Security "max-age=15768000"
SSLEngine on
SSLCertificateFile /etc/letsencrypt/live/team.example.com/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/team.example.com/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/team.example.com/chain.pem
SSLProtocol             all -SSLv2 -SSLv3
SSLCipherSuite          ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS
SSLHonorCipherOrder     on
SSLCompression          off
</VirtualHost>